A026866 a(n) = T(2n+1,n+2), T given by A026747.

1, 6, 29, 132, 589, 2613, 11592, 51558, 230181, 1032060, 4648150, 21027765, 95542878, 435939525, 1997076805, 9183661080, 42383777344, 196271453865, 911804206063, 4248637465050, 19852810349837, 93012949698861, 436860932671829

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Comments

This appears to obey a hypergeometric 8-term recurrence with 4th-order polynomial coefficients. - R. J. Mathar, Nov 10 2013

Crossrefs

Cf. A026747.