51624

Appears in sequences

• Expansion of 1/Product_{m>=1} (1 - m*q^m)^27.at n=4A022751
• Numbers k such that k and k+1 have the same sum of squarefree divisors, or sqf(k) = sqf(k+1), where sqf(k) = A048250(k).at n=16A063964
• 3-apexes of Omega: numbers k such that Omega(k-3) < Omega(k-2)< Omega(k-1) < Omega(k) > Omega(k+1) > Omega(k+2) > Omega(k+3), where Omega(m) = the number of prime factors of m, counting multiplicity.at n=12A076760
• Heptagonal numbers for which the sum of the digits is also a heptagonal number.at n=36A117650
• a(n) = Sum_{k=0..n} F(k+1)^2*F(n-k+1)^2 where F = Fibonacci numbers (A000045).at n=10A136429
• a(n) = (n + 1)^2*(5*n^2 + 10*n + 2)/2.at n=11A269237
• Numbers k such that k and k+1 have the same average of unitary divisors.at n=30A349222