login
A292119
O.g.f. equals the square of the e.g.f. of A291561.
1
1, 10, 130, 2100, 40950, 943740, 25269300, 774635400, 26836251750, 1038607069500, 44448725821500, 2084869401615000, 106355178306877500, 5861473946222895000, 346999395775257225000, 21956626245257906202000, 1478562610889805715023750, 105561794005139231136877500, 7963731010308915234880987500, 632966979266333111428303275000, 52862553418201438508049805852500
OFFSET
2,2
COMMENTS
A291561 is a diagonal in triangle A291560: a(n) = -A291560(n+1, n) for n >= 1; the e.g.f. of triangle A291560 equals arcsin( k*sin(x) ).
EXAMPLE
O.g.f.: A(x) = x^2 + 10*x^3 + 130*x^4 + 2100*x^5 + 40950*x^6 + 943740*x^7 + 25269300*x^8 + 774635400*x^9 + 26836251750*x^10 + 1038607069500*x^11 + 44448725821500*x^12 + 2084869401615000*x^13 + 106355178306877500*x^14 + 5861473946222895000*x^15 + 346999395775257225000*x^16 + 21956626245257906202000*x^17 + 1478562610889805715023750*x^18 + ...
such that the square root of the g.f. equals the e.g.f. of A291561, which begins:
A(x)^(1/2) = x + 10*x^2/2! + 315*x^3/3! + 18900*x^4/4! + 1819125*x^5/5! + 255405150*x^6/6! + 49165491375*x^7/7! + 12417798393000*x^8/8! + 3981456609755625*x^9/9! + 1579311121869731250*x^10/10! + ... + A291561(n)*x^n/n! + ...
PROG
(PARI) {A291560(n, r) = (2*n-1)! * polcoeff( polcoeff( asin( k*sin(x + O(x^(2*n)))), 2*n-1, x), 2*r-1, k)}
{a(n) = polcoeff( sum(m=1, n, -A291560(m+1, m) * x^m / m! +x*O(x^n) )^2, n)}
for(n=2, 25, print1(a(n), ", "))
CROSSREFS
Sequence in context: A327810 A355422 A051607 * A113386 A302615 A281395
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Sep 18 2017
STATUS
approved