A192733 Euler transform is sequence A004016.

6, -21, 76, -345, 1734, -8906, 46662, -250257, 1365388, -7538421, 42030150, -236312690, 1338000774, -7620721077, 43626920908, -250869973089, 1448248263558, -8389624496618, 48751103123142, -284073748405401, 1659452645344972, -9715933503018165

Offset: 1

Author

Michael Somos, Jul 08 2011

Keywords

• sign

Crossrefs

Cf. A004016.

Programs

PARI

{a(n) = local(A, S); if( n<1, 0, A = 1 + x * O(x^n); S = sum( k= 1, n, 6 * sumdiv( k, d, kronecker( d, 3)) * x^k, A); for( k = 1, n-1, S *= (A - x^k) ^ polcoeff( S, k)); polcoeff( S, n))}

Formula

a(q) = Prod_{k>0} (1 - q^k)^-a(k).