417697

Appears in sequences

• Initial terms of chains consisting of four consecutive integers, for none of which is the value of sigma-function divisible by six.at n=20A097020
• a(1)=a(2)=1; a(n) = a(n-2) + a(n-1) + (number of terms from among {a(1), a(2), ..., a(n-1)} which are prime).at n=26A128609