A012860 Numerators of coefficients in Taylor series expansion of log(cosec(x)*tanh(x)).

0, -1, 1, -61, 17, -1021, 691, -32762, 929569, -1045394477, 221930581, -651651769166, 56963745931, -88306000053182, 2093660879252671, -321780490474593819308, 129848163681107301953, -2604961188011595075731, 209390615747646519456961, -7707087027623315087276182, 16103843159579478297227731

Offset

0,4

Links

Table of n, a(n) for n=0..20.

Example

-1/6*x^2+1/12*x^4-61/2835*x^6+17/2520*x^8-1021/467775*x^10+691/935550*x^12-...

Maple

t1:=log(tanh(x)*csc(x));
t2:=series(t1, x, 50);
t3:=seriestolist(t2);
t3:=[seq(t3[2*i+1], i=0..(nops(t3)-1)/2 )];
t4:=map(numer, t3); t5:=map(denom, t3); lprint(t2);

Crossrefs

Cf. A202383.

Sequence in context: A106416 A224730 A248143 * A002108 A087409 A199749

Adjacent sequences: A012857 A012858 A012859 * A012861 A012862 A012863

Keyword

sign,frac

Author

Patrick Demichel (patrick.demichel(AT)hp.com)

Extensions

Corrected by N. J. A. Sloane, Dec 18 2011, based on discussions on the Sequence Fans Mailing List, Dec 13-17 2011.

Status

approved