A369732 Number of solutions to +- 1^4 +- 2^4 +- 3^4 +- ... +- n^4 = 1.

0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 21, 0, 0, 126, 0, 0, 0, 0, 1428, 0, 0, 9786, 7, 0, 0, 22, 150437, 0, 0, 836737, 1838, 0, 0, 15847, 14696425, 0, 0, 83010230, 738627, 0, 0, 6024822, 1640652994, 0, 0, 10271377082, 226033104, 0, 0

Offset: 0

Author

Ilya Gutkovskiy, Jan 30 2024

Keywords

• nonn

Crossrefs

Cf. A000583, A063866, A111253, A158465, A368206, A369629, A369730, A369731.

Formula

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

Extensions

a(46)-a(60) from Alois P. Heinz, Jan 30 2024