|*| a(j, p, 2) = Somme_{k= 1..[2*j +1 +(-1)^(j-1)]/4} [ C(j-1, 2*k -2) * C(j +3 -2*k, j +1 -2*k)^(p-1) <= formule générale des coefficients sobaliens
|*| - C(j-1, 2*k -1) * C(j +2 -2*k, j -2*k)^(p-1) ] ( pour q = 2, triangulaires )
Exemple pour p = 5 :
-------------------------
[ coefficients sobaliens ]
a(1,5,2) = 1
a(2,5,2) = 3^4 -1 = 80
a(3,5,2) = 3^4*[2^4-2] +1 = 1135
a(4,5,2) = [5!/(3!2!)]^(5-1) -3*[4!/(2!2!)]^(5-1) +3*3^(5-1) -1 = 6354
a(5,5,2) = C(6,4)^4 -4*C(5,3)^4 +6*C(4,2)^4 -4*C(3,1)^4 +C(2,0)^4
= 15^4 -4*10^4 +6*6^4 -4*3^4 +1
= 50625 -40000 +7776 -324 +1 = 18078
a(6,5,2) = C(7,5)^4 -5*C(6,4)^4 +10*C(5,3)^4 -10*C(4,2)^4 +5*C(3,1)^4 -C(2,0)^4
= 21^4 -5*15^4 +10*10^4 -10*6^4 +5*3^4 -1
= 194481 -253125 +100000 -12960 +405 -1 = 28800
. . . . . . .
a(7,5,2) = C(8,6) -6*C(7,5)^4 +15*C(6,4)^4 -20*C(5,3)^4 +15*C(4,2)^4 -6*C(3,1)^4 +1*C(2,0)^4 = 26100
= [ (6*5^4 -20*5^3 +21*5^2 -7*5)*6! ]/[ 3*2^4 ] = 26100
. . . . . . .
a(8,5,2) = 5*8!/(2!)^4 =12600
= [ (5^2-5)*7! ]/2^3 = 12600
a(9,5,2) = 8!/(2!)^4 = 2520
= 4*7!/2^3 = 2520
_>
Somme_{i=1..n} C(i +1, 2)^5 = 3 * [ C(n+2, 3) ] * [ 1/3 +(80/4)*C(n-1, 1) +(1135/5)*C(n-1, 2) +(6354/6)*C(n-1, 3)
+(18078/7)*C(n-1, 4) +(28800/8)*C(n-1, 5) +(26100/9)*C(n-1, 6)
+(12600/10)*C(n-1, 7) +(2520/11)*C(n-1,8) ]
Exemple pour n = 7 : ( voir OEIS - A085440 ) -------------------------
Somme_{i=1..7} C(i +1, 2)^5 = a(7) = 1^5 +3^5 +6^5 +10^5 +15^5 +21^5 +28^5
= 3 * [ C(9, 3)] * [ 1/3 +20*6 +227*15 +1059*20 +(18078/7)*15 +3600*6 +2900*1
+1250*0 +(2520/11)*0 ]
= 3 * [ 84 ] * [ 1/3 +... +2900 +0 +0 ]
= 84 +30240 +858060 +5337360 +9762120 +9762120 +5443200 +730800 +0 +0
= 22161864
1=a(1,1,2),
1=a(1,2,2), 2=a(2,2,2), 1=a(3,2,2),
1=a(1,3,2), 8=a(2,3,2), 19=a(3,3,2), 18=a(4,3,2), 6=a(5,3,2),
1, 26, 163, 432, 564, 360, 90=a(7,4,2),
1, 80, 1135, 6354, 18078, 28800, 26100, 12600, 2520=a(9,5,2),
1, 242, 7291, 77400, 405060, 1210680, 2211570, 2520000, 1751400, 680400, 113400 = a(11,6,2),
1, 728, 45199, 862218, 7667646, 38350080, 118848420, 239992200, 322176960, 285768000,
___161141400, 52390800, 7484400 = a(13,7,2),
1, 2186, 275563, 9166752, 132530244, 1044003240, 5053473810, 16100582400, 35105157360,
___53352885600, 56567775600, 41074387200, 19489377600, 5448643200, 681080400 = a(15,8,2),
1, 6560, 1666495, 94980834, 2172942078, 25991642880, 187333356420, 884539567800, 2880471280680,
___6673493836800, 11182022686800, 13605157288800, 11914610954400, 7322976460800, 2999478081600,
___735566832000, 81729648000 = a(17,9,2),
1, 19682, 10038331, 969825960, 34503746820, 611962571160, 6369577111890, . . . . ., 572516184240000,
___125046361440000, 12504636144000 = a(19,10,2),
1, a(2,11,2) = 59048 = 3^10-1, a(3,11,2) = 60348079, a(4,11,2) = 9818778618, . . . . ., a(19,11,2), a(20,11,2),
___a(21,11,2) = 2375880867360000,
1, a(2,12,2) =177146 = 3^11-1, a(3,12,2) = 362442763, a(4,12,2), . . . . ., a(21,12,2), a(22,12,2),
___ a(23,12,2) = 548828480360160000,
1, a(2,13,2), a(3,13,2), a(4,13,2), . . . . ., a(23,13,2), a(24,13,2), a(25,13,2),
1, . . . . .,