A261420 - OEIS

A261420

Numerators of coefficients in Taylor series expansion of sqrt( 1 + Sum_{k>=1} (k*(k+1)/2)*x^k ).

1, 1, 11, 37, 371, 735, 2463, 4397, 91075, 280123, 1437381, 2529811, 8602103, -3127477, 52126151, 605095485, 34771603043, 53033530323, -118339970967, -925189527433, -4874069151427, 19698401278369, 210735914741353, 332611270169019, -5351278899565017, -36333411498508817

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

LINKS

Table of n, a(n) for n=0..25.

EXAMPLE

The coefficients are 1, 1/2, 11/8, 37/16, 371/128, 735/256, 2463/1024, 4397/2048, 91075/32768, 280123/65536, 1437381/262144, 2529811/524288, 8602103/4194304, -3127477/8388608, 52126151/33554432, 605095485/67108864, 34771603043/2147483648, ... [corrected by Ilya Gutkovskiy, Aug 03 2023]

CROSSREFS

The denominators appear to be A046161.

Sequence in context: A147556 A201312 A120833 * A034969 A052432 A104269

Adjacent sequences: A261417 A261418 A261419 * A261421 A261422 A261423

KEYWORD

sign,frac

AUTHOR

N. J. A. Sloane, Aug 27 2015

STATUS

approved