123205

Appears in sequences

• a(n) = sigma_4(n^2)/sigma_2(n^2).at n=19A084218
• a(n) = 2*n^3 - 3*n^2 + 5.at n=40A152064
• Expansion of 1/(1 - 22*x + 81*x^2), used in A246643.at n=4A246645
• Numbers n such that there is no other number k for which A155043(k) = A155043(n).at n=33A262509
• Parent nodes of nonzero terms of A262509: a(n) = A049820(A262509(n)).at n=33A262510