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A280795 E.g.f. A(x) = F(x)^2, where F(F(x)) = sin(x). 2
2, -4, -4, -64, -1392, -36048, -68288, 217764736, 45152039424, 6761531610496, 479656304761728, -181164506307765760, -94510602811595547648, -9099359091145965684736, 15760449987522859047213056, 8420566548360384773538111488, -5361092182457081839427169370112, -9833526816807364784720991628738560, 595009928118250648162581567581609984 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

This sequence appears to consist entirely of integers.

LINKS

Paul D. Hanna, Table of n, a(n) for n = 1..100

EXAMPLE

E.g.f.: A(x) = 2*x^2/2! - 4*x^4/4! - 4*x^6/6! - 64*x^8/8! - 1392*x^10/10! - 36048*x^12/12! - 68288*x^14/14! + 217764736*x^16/16! + 45152039424*x^18/18! + 6761531610496*x^20/20! +...

where A(x) = F(x)^2 such that F(F(x)) = sin(x) and F(x) begins:

F(x) = x - 1/2*x^3/3! - 3/4*x^5/5! - 53/8*x^7/7! - 1863/16*x^9/9! - 92713/32*x^11/11! - 3710155/64*x^13/13! + 594673187/128*x^15/15! + 329366540401/256*x^17/17! + 104491760828591/512*x^19/19! + 19610322215706989/1024*x^21/21! +...

PROG

(PARI) {a(n)=local(A, B, F); F=sin(x+O(x^(2*n+1))); A=F; for(i=0, 2*n-1, B=serreverse(A); A=(A+subst(B, x, F))/2); if(n<1, 0, (2*n)!*polcoeff(A^2, 2*n, x))}

for(n=1, 30, print1(a(n), ", "))

CROSSREFS

Cf. A098932, A280796.

Sequence in context: A155952 A277445 A145636 * A059052 A292017 A285616

Adjacent sequences:  A280792 A280793 A280794 * A280796 A280797 A280798

KEYWORD

sign

AUTHOR

Paul D. Hanna, Jan 13 2017

STATUS

approved

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Last modified December 6 18:03 EST 2019. Contains 329809 sequences. (Running on oeis4.)