OFFSET
1,3
EXAMPLE
a(3) = a(2) + gpf(1 + a(1)) = 1 + gpf(1 + 1) = 1 + 2 = 3.
a(4) = a(3) + gpf(1 + a(1) * a(2)) = 3 + gpf(1 + 1 * 1) = 3 + 2 = 5.
a(5) = a(4) + gpf(1 + a(1) * a(2) * a(3)) = 5 + gpf(1 + 1 * 1 * 3) = 5 + 2 = 7.
PROG
(PARI) gpf(n)=my(f=factor(n)[, 1]); f[#f];
a(n)=if(n>2, a(n-1)+gpf(1+prod(i=1, n-2, a(i))), 1)
first(m)=my(v=vector(m)); v[1]=1; v[2]=1; for(i=3, m, v[i]=v[i-1]+gpf(1+prod(k=1, i-2, v[k]))); v
CROSSREFS
KEYWORD
nonn
AUTHOR
Anders Hellström, Nov 22 2015
STATUS
approved