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
KEYWORD
nonn
AUTHOR
Chris Kunferman, Feb 17 2013
STATUS
approved