A133516 Recurring combinations: a(n) = C(a(n-1),a(n-2)).

2, 5, 10, 252, 237517990691968350

Offset

0,1

Comments

A049022 is the same formula, but with initial values 2, 4.

Links

Table of n, a(n) for n=0..4.

Mathematica

nxt[{a_, b_}]:={b, Binomial[b, a]}; Transpose[NestList[nxt, {2, 5}, 4]][[1]] (* Harvey P. Dale, Jan 23 2015 *)

Crossrefs

Cf. A049022.

Sequence in context: A018773 A174475 A133035 * A342489 A342612 A342490

Adjacent sequences: A133513 A133514 A133515 * A133517 A133518 A133519

Keyword

easy,nonn

Author

Jonathan Vos Post, Nov 30 2007

Extensions

Corrected by Harvey P. Dale, Jan 23 2015

Status

approved