0,2

Enters 5-cycle 20,19,28,30,21 starting with a(20).

Table of n, a(n) for n=0..76.

a(n) = a(n-5) for n >= 25.

a(n+1) = A001414(a(n)*a(n-1)).

a(5) = A001414(6) + A001414(4) = 5 + 4 = 9.

spf:= n -> add(t[1]*t[2], t=ifactors(n)[2]):

N:= 100:

A:= Array(0..N): A[0]:= 1: A[1]:= 2:

for n from 2 to N do

A[n]:= spf(A[n-1])+spf(A[n-2])

od:

seq(A[i], i=0..N);

Cf. A001414, A338938.

Sequence in context: A337723 A222735 A299408 * A319381 A340496 A035564

Adjacent sequences: A338934 A338935 A338936 * A338938 A338939 A338940

nonn

J. M. Bergot and Robert Israel, Nov 16 2020

approved