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%I #8 Jun 11 2020 03:17:37
%S 1,3,18,2268,13608,1857492,133739424,53362030176,640344362112,
%T 561902177753280,23599891465637760,17558319250434493440,
%U 442469645110949234688,6065595130003447583720448,2547549954601447985162588160,985901832430760370257921617920,23661643978338248886190118830080
%N 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).
%D 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.
%e 1/cm(w) = 1 + (1/3)*w^3 + (1/18)*w^6 + (23/2268)*w^9 + (25/13608)*w^12 + (619/1857492)*w^15 + ...
%o (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]));
%Y Cf. A104133, A104134, A335157, A335158, A335180.
%K nonn,frac
%O 0,2
%A _Michel Marcus_ and _N. J. A. Sloane_, Jun 10 2020
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