A335180 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) = numerator of b(3*n).

1, 1, 1, 23, 25, 619, 8083, 584929, 1273037, 202602551, 1543302079, 208247895067, 951782914315, 2366380533924005, 180256368687985157, 12651975031966998901, 55071424621489369589, 3670628209891560101791, 93468279611939477215967, 67638487586433857706623771

Offset

0,4

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..19.

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) anum(nn) = my(A = O(x)); for(i=0, nn, A = 1 - intformal(intformal(A^2)^2)); my(v=Vec(1/A)); apply(x->numerator(x), vector(#v\3, k, v[3*k-2])); \\ Michel Marcus, Jun 10 2020

Crossrefs

Cf. A104133, A104134, A335157, A335158, A335181.

Sequence in context: A112073 A050864 A111452 * A147627 A359510 A345489

Adjacent sequences: A335177 A335178 A335179 * A335181 A335182 A335183

Keyword

nonn,frac

Author

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

Status

approved