OFFSET
1,4
PROG
(PARI) t(n)=n*(n+1)/2 v=vector(12) v[2]=1 for (i=3, 12, v[i]=t(v[i-1])+t(v[i-2])) v
CROSSREFS
KEYWORD
nonn
AUTHOR
Jon Perry, Mar 13 2004
STATUS
approved