A123616 Column 6 of triangle A123610.

1, 7, 100, 786, 4420, 19404, 71188, 226512, 644231, 1670015, 4008200, 9009728, 19146090, 38744496, 75117600, 140218218, 253051227, 443056383, 754838884, 1254576400, 2038689796, 3245256396, 5069041432, 7780827600, 11752298725

Offset

0,2

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

Formula

G.f.: P_6(x) / ((1-x)*(1-x^2)*(1-x^3)*(1-x^4)*(1-x^5)*(1-x^6))^2, with P_6(1) = 11!, where P_6(x) = (1+5*x+85*x^2+581*x^3+2763*x^4+9987*x^5+29644*x^6+74546*x^7+ 164629*x^8+324255*x^9+579250*x^10+946960*x^11+1429875*x^12+2003713*x^13+ 2620218*x^14+3205496*x^15+3679773*x^16+3967701*x^17+4024087*x^18+ 3837087*x^19+3440204*x^20+2894878*x^21+2283089*x^22+1681653*x^23+ 1153208*x^24+731684*x^25+427027*x^26+226843*x^27+108486*x^28+45806*x^29+ 16737*x^30+5073*x^31+1221*x^32+211*x^33+23*x^34+x^35).

Prog

(PARI) {a(n)=polcoeff(truncate(Ser([1, 5, 85, 581, 2763, 9987, 29644, 74546, 164629, 324255, 579250, 946960, 1429875, 2003713, 2620218, 3205496, 3679773, 3967701, 4024087, 3837087, 3440204, 2894878, 2283089, 1681653, 1153208, 731684, 427027, 226843, 108486, 45806, 16737, 5073, 1221, 211, 23, 1])) / ((1-x)^2*(1-x^2)^2*(1-x^3)^2*(1-x^4)^2*(1-x^5)^2*(1-x^6)^2 +x*O(x^n)), n)}

Crossrefs

Cf. A123610 (triangle); columns: A005997, A123613, A123614, A123615.

Sequence in context: A115066 A340887 A272957 * A001594 A297151 A052752

Adjacent sequences: A123613 A123614 A123615 * A123617 A123618 A123619

Keyword

nonn

Author

Paul D. Hanna, Oct 03 2006

Status

approved