A335181 Define b(n) by 1/cm(w) = Sum_{n >= 0} b(3*n)*w^(3*n), where cm(w) is the elliptic function defined in A104134; a(n) = denominator of b(3*n).

1, 3, 18, 2268, 13608, 1857492, 133739424, 53362030176, 640344362112, 561902177753280, 23599891465637760, 17558319250434493440, 442469645110949234688, 6065595130003447583720448, 2547549954601447985162588160, 985901832430760370257921617920, 23661643978338248886190118830080

Offset

0,2

References

Oscar S. Adams, Elliptic Functions Applied to Conformal World Maps, Special Publication No. 112 of the U.S. Coast and Geodetic Survey, 1925. See pp. 3-4.

Links

Table of n, a(n) for n=0..16.

Example

1/cm(w) = 1 + (1/3)*w^3 + (1/18)*w^6 + (23/2268)*w^9 + (25/13608)*w^12 + (619/1857492)*w^15 + ...

Prog

(PARI) aden(nn) = my(A = O(x)); for(i=0, nn, A = 1 - intformal(intformal(A^2)^2)); my(v=Vec(1/A)); apply(x->denominator(x), vector(#v\3, k, v[3*k-2]));

Crossrefs

Cf. A104133, A104134, A335157, A335158, A335180.

Sequence in context: A069854 A316369 A291078 * A297536 A157556 A214442

Adjacent sequences: A335178 A335179 A335180 * A335182 A335183 A335184

Keyword

nonn,frac

Author

Michel Marcus and N. J. A. Sloane, Jun 10 2020

Status

approved