A261421 Numerators of coefficients in Taylor series expansion of sqrt(m(x)) where m(x) is g.f. for Motzkin numbers A001006.

1, 1, 7, 25, 427, 1911, 18051, 87945, 3518515, 17943211, 185961113, 976288495, 20727407743, 111039591475, 1199227922235, 6520801221225, 570761912807235, 3139190488028595, 34696316039725725, 192564553799569875, 4291438629174301605, 23993043241870766505, 269139354637637831685

Offset

0,3

Links

Table of n, a(n) for n=0..22.

Example

The coefficients are [1, 1/2, 7/8, 25/16, 427/128, 1911/256, 18051/1024, 87945/2048, 3518515/32768, 17943211/65536, 185961113/262144, 976288495/524288, 20727407743/4194304,  111039591475/8388608, 1199227922235/33554432, 6520801221225/67108864,  ...

Crossrefs

The denominators appear to be A046161. Cf. A001006.

Sequence in context: A231579 A364644 A197721 * A081298 A318633 A300527

Adjacent sequences: A261418 A261419 A261420 * A261422 A261423 A261424

Keyword

sign,frac

Author

N. J. A. Sloane, Aug 27 2015

Extensions

Name corrected by Werner Schulte, Oct 24 2022

Status

approved