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

Author

N. J. A. Sloane, Aug 27 2015

Keywords

• sign
• frac

Examples

			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.

Extensions

Name corrected by Werner Schulte, Oct 24 2022