A087189 (P(p)-1)/2/p^2 where p runs through the odd primes different from 5 and P(k) is the k-th central pentanomial coefficient (A005191).

1, 83, 16907, 279021, 89444018, 1695011087, 658067703933, 5768410509553937, 122108313460051500, 1226978854222034501448, 593538703869555995238872, 13175226571428140572866093, 6594852118968926152838341468, 76339779380132942579800334346403

Offset: 1

Author

Benoit Cloitre, Oct 19 2003

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..226 (terms 1..100 from M. F. Hasler)

Crossrefs

Cf. A005191.

Programs

Mathematica

f[n_] := Max[CoefficientList[Expand[Sum[x^k, {k, 0, 4}]^n], x]]; Table[(f[p] - 1)/(2*p^2), {p, Prime[Delete[Range[2, 15], 2]]}] (* Amiram Eldar, Apr 22 2025 *)

PARI

A087189(n) = local(p=prime(n+2-(n==1))); (A005191(p)-1)/2/p^2 \\ M. F. Hasler, Jul 23 2007

Extensions

Corrected and extended by M. F. Hasler, Jul 23 2007