OFFSET
0,4
LINKS
Harry J. Smith, Table of n, a(n) for n = 0..28
MATHEMATICA
RecurrenceTable[{a[0]==a[1]==a[2]==1, a[n]==a[n-1]+(1+a[n-2])(1+ a[n-3])}, a, {n, 20}] (* Harvey P. Dale, Feb 27 2012 *)
PROG
(PARI) { a=a3=a2=a1=1; for (n = 0, 28, if (n>2, a=a1 + (1 + a2)*(1 + a3); a3=a2; a2=a1; a1=a); write("b063404.txt", n, " ", a) ) } \\ Harry J. Smith, Aug 20 2009
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Olivier Gérard, Jul 16 2001
EXTENSIONS
One additional term from Harvey P. Dale, Feb 27 2012
STATUS
approved