118910

Appears in sequences

• 5-dimensional pyramidal numbers: a(n) = n*(n+1)*(n+2)*(n+3)*(2n+3)/5!.at n=21A005585
• a(n) = (11*n + 4)*C(n+3, 3)/4.at n=21A055268
• Numbers k such that Sum_{d divides k} sigma(d)/phi(d) is an integer.at n=34A068991
• Convolution of A008805 (triangular numbers repeated) with itself.at n=42A177747
• Antidiagonal sums of the convolution array A213833.at n=21A213834
• Squarefree nonprimes n with a divisor d such that phi(n) divides n+d.at n=37A217741
• Squarefree numbers (from A005117) with prime divisors in a 2p+1 progression.at n=22A231966
• a(n) = the smallest squarefree number (A005117) with n prime factors in a 2p+1 progression.at n=4A231969
• Numbers k, not powers of primes, for which A011772(k) divides A344875(k), and for all proper divisors d of k, A011772(d) < A011772(k).at n=17A344694