A262310 a(n) = coefficient of x^(2n) in the expansion of the modular form Product_{k>=1} (1-x^k)^n.

1, -1, 1, -7, 9, 9, 49, -176, 57, -673, 2401, 1143, -9063, 33201, -153502, 315783, -755943, 2210985, -767039, 1790369, -40127031, 44496424, -58813391, 1040502519, -1696965207, -1810005816, -4483997699, 7445790947, 105920054242, -134133273672, -203398909151

Offset

0,4

Links

Table of n, a(n) for n=0..30.

Maple

C7:=proc(r) local t1, n;
t1:=mul((1-x^n)^r, n=1..2*r+2);
series(t1, x, 2*r+1);
coeff(%, x, 2*r);
end;
[seq(C7(i), i=0..30)];

Crossrefs

Bisections: A262537, A262538.

Sequence in context: A121313 A111204 A000510 * A167628 A112954 A031952

Adjacent sequences: A262307 A262308 A262309 * A262311 A262312 A262313

Keyword

sign

Author

N. J. A. Sloane, Oct 04 2015

Status

approved