A157062 Number of integer sequences of length n+1 with sum zero and sum of absolute values 26.

2, 78, 1692, 25740, 302850, 2912910, 23744840, 168278760, 1056789450, 5968878630, 30684132468, 144977296932, 634756203018, 2593322651430, 9946019437200, 35995371261360, 123490242018990, 403237594259010, 1257743358034100, 3759426449644740, 10799525727846702

Offset: 1

Author

R. H. Hardin, Feb 22 2009

Keywords

• nonn

Links

• T. D. Noe, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (27,-351,2925,-17550,80730,-296010,888030,-2220075, 4686825,-8436285,13037895,-17383860,20058300,-20058300,17383860,-13037895, 8436285,-4686825,2220075,-888030,296010,-80730,17550,-2925,351,-27,1).

Crossrefs

Cf. A103881, A156554.

Programs

Mathematica

A103881[n_, k_]:= (n+1)*Binomial[n+k-1,k]*HypergeometricPFQ[{1-n,-n,1-k}, {2, 1-n - k}, 1];
A157062[n_]:= A103881[n, 13];
Table[A157062[n], {n, 50}] (* G. C. Greubel, Jan 24 2022 *)

Sage

def A103881(n,k): return sum( binomial(n+1, i)*binomial(k-1, i-1)*binomial(n-i+k, k) for i in (0..n) )
def A157062(n): return A103881(n, 13)
[A157062(n) for n in (1..50)] # G. C. Greubel, Jan 24 2022

Formula

a(n) = T(n,13); T(n,k) = Sum_{i=1..n} binomial(n+1, i)*binomial(k-1, i-1)*binomial(n-i+k, k).

From G. C. Greubel, Jan 24 2022: (Start)

a(n) = (n+1)*binomial(n+12, 13)*Hypergeometric3F2([-12, -n, 1-n], [2, -n-12], 1).

a(n) = (10400600/26!)*n*(n+1)*(2982752926433280000 + 6502800338141184000*n + 10192999816651161600*n^2 + 8194549559065989120*n^3 + 6217354001317404672*n^4 + 2785907939555600640*n^5 + 1345736958526293696*n^6 + 386128480881709632*n^7 + 133329525393692848*n^8 + 26155830342678960*n^9 + 6893260441243396*n^10 + 955286585044572*n^11 + 200534847420673*n^12 + 19880275030680*n^13 + 3426180791086*n^14 + 242021337492*n^15 + 35027635423*n^16 + 1724131200*n^17 + 213288856*n^18 + 6959172*n^19 + 746383*n^20 + 14520*n^21 + 1366*n^22 + 12*n^23 + n^24).

G.f.: 2*x*(1 + 12*x + 144*x^2 + 792*x^3 + 4356*x^4 + 14520*x^5 + 48400*x^6 + 108900*x^7 + 245025*x^8 + 392040*x^9 + 627264*x^10 + 731808*x^11 + 853776*x^12 + 731808*x^13 + 627264*x^14 + 392040*x^15 + 245025*x^16 + 108900*x^17 + 48400*x^18 + 14520*x^19 + 4356*x^20 + 792*x^21 + 144*x^22 + 12*x^23 + x^24)/(1-x)^27. (End)