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
Keywords
Programs
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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)];