A368206 a(n) = [x^n] Product_{k=1..n} (x^(k^4) + 1/x^(k^4)).

1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 8, 13, 0, 0, 272, 0, 0, 0, 5400, 8915, 0, 0, 30433, 1590, 0, 0, 68638, 73470, 0, 0, 90808, 6638072, 0, 0, 127356, 319803, 0, 0, 20130146, 559282596, 0, 0, 1507066936, 3820244957, 0, 0

Offset

0,22

Links

Table of n, a(n) for n=0..59.

Maple

b:= proc(n, i) option remember; (m-> `if`(n>m, 0, `if`(n=m, 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-> `if`(irem(n, 4)>1, 0, b(n, n)):
seq(a(n), n=0..43);  # Alois P. Heinz, Jan 25 2024

Crossrefs

Cf. A000583, A063890, A158465, A348165, A348892.

Sequence in context: A081550 A252244 A019929 * A021866 A258760 A328907

Adjacent sequences: A368203 A368204 A368205 * A368207 A368208 A368209

Keyword

nonn

Author

Ilya Gutkovskiy, Jan 25 2024

Extensions

a(46)-a(59) from Alois P. Heinz, Jan 25 2024

Status

approved