A209286 a(n) = a(n-1) + (1+a(n-2))*a(n-3) for n>1, a(1) = 1, a(n) = 0 for n<1.

0, 1, 1, 1, 3, 5, 9, 27, 77, 329, 2435, 27845, 829289, 68634299, 23160214349, 56940830227049, 1589642017432217699, 1318763422910513770158149, 90515537555154997905172366725449, 2096361748201801549831377117539292825822299

Offset

0,5

Links

Alois P. Heinz, Table of n, a(n) for n = 0..30

Formula

a(n) = a(n-1) + (1+a(n-2))*a(n-3) for n>1, a(1) = 1, a(n) = 0 for n<1.

Maple

a:= proc(n) a(n):= `if`(n<1, 0,
      `if`(n=1, 1, a(n-1) +(1+a(n-2))*a(n-3)))
    end:
seq(a(n), n=0..20);  # Alois P. Heinz, Feb 20 2013

Mathematica

Rest[RecurrenceTable[{a[-1]==a[0]==0, a[1]==1, a[n]==a[n-1]+(1+a[n-2]) a[n-3]}, a, {n, 20}]] (* Harvey P. Dale, Apr 13 2014 *)

Crossrefs

Sequence in context: A217098 A262314 A338604 * A082711 A013622 A246666

Adjacent sequences: A209283 A209284 A209285 * A209287 A209288 A209289

Keyword

nonn

Author

Chris Kunferman, Feb 17 2013

Status

approved