247221

Appears in sequences

• Numbers k such that sopf(k) = sopf(k^2 - 1), where sopf(k) = A008472(k).at n=22A064019
• Sequence defined by the recurrence formula a(n+1)=sum(a(p)*a(n-p)+k,p=0..n)+l for n>=1, with here a(0)=1, a(1)=2, k=1 and l=-1.at n=10A176828