4697616

Appears in sequences

• Let S(n)=sigma(|n|)-3*n; sequence gives numbers n such that S(S(S(S(n))))=n. May be called {3,1}-Sociable number of orders 1 or 2 or 4.at n=10A114528
• a(n) = 4*(3*n+2)*(2*n+1)*(n+2)*(n+1).at n=21A155122
• a(n) is the Severi degree for curves of degree n and cogenus 2.at n=32A171108