A369517 a(n) = [x^(n^4)] Product_{k=1..n} (x^(k^4) + 1 + 1/x^(k^4)).

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 9, 20, 43, 85, 183, 394, 1010, 2254, 5589, 12383, 31226, 71153, 182382, 426055, 1105686, 2615167, 6906858, 16607500, 44276140, 107836782, 290059089, 715361182, 1937639649, 4829754357, 13160903826, 33112002835, 90800047879

Offset

0,10

Links

Table of n, a(n) for n=0..37.

Maple

b:= proc(n, i) option remember; (m-> `if`(n>m, 0, `if`(n=m, 1, b(n, i-1)+
      b(abs(n-i^4), i-1)+b(n+i^4, i-1))))(i*(i+1)*(2*i+1)*(3*i^2+3*i-1)/30)
    end:
a:= n-> b(n^4, n):
seq(a(n), n=0..33);  # Alois P. Heinz, Jan 25 2024

Crossrefs

Cf. A000583, A316706, A369358, A369434, A369438.

Sequence in context: A006866 A121908 A231368 * A245123 A097075 A036673

Adjacent sequences: A369514 A369515 A369516 * A369518 A369519 A369520

Keyword

nonn

Author

Ilya Gutkovskiy, Jan 25 2024

Extensions

a(34)-a(37) from Alois P. Heinz, Jan 25 2024

Status

approved