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A013525 E.g.f.: x + (gdinv x - sinh x)/2, where gdinv = inverse-Gudermannian. Sequence has odd-indexed coefficients; others are zero. +0
2
1, 0, 2, 30, 692, 25260, 1351382, 99680490, 9695756072, 1202439837720, 185185594118762, 34674437196568950, 7757267081778543452, 2043536254646561946180, 626129820701814932734142, 220771946624511552276841410 (list; graph; listen)
OFFSET

0,3

COMMENT

Also gdinv(x) = log(tan(x)+sec(x)).

FORMULA

For n>0, a(n) = (1/2) * (A000364(n) - 1).

EXAMPLE

x + (gdinv x - sinh x)/2 = x+2/5!*x^5+30/7!*x^7+692/9!*x^9...

CROSSREFS

Sequence in context: A099046 A020547 A160694 this_sequence A114938 A082653 A140174

Adjacent sequences: A013522 A013523 A013524 this_sequence A013526 A013527 A013528

KEYWORD

nonn,easy

AUTHOR

Patrick Demichel (dml(AT)hpfrcu03.france.hp.com)

EXTENSIONS

Definition corrected by Ralf Stephan and Don Reble, Dec 16 2004

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Last modified December 13 23:45 EST 2009. Contains 170824 sequences.


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