A009561 Index of central binomial coefficient C(2n,n) within A006987.

1, 4, 13, 28, 61, 119, 226, 423, 790, 1472, 2764, 5224, 9956, 19112, 36923, 71703, 139835, 273625, 536860, 1055588, 2079066, 4100573, 8096789, 16002500, 31652194, 62648225, 124068499, 245826760

Offset

2,2

Links

Table of n, a(n) for n=2..29.

Crossrefs

Sequence in context: A212578 A372484 A112560 * A155266 A155413 A155326

Adjacent sequences: A009558 A009559 A009560 * A009562 A009563 A009564

Keyword

nonn

Author

David W. Wilson

Status

approved