161820

Appears in sequences

• 4-dimensional figurate numbers: a(n) = (5*n-1)*binomial(n+2,3)/4.at n=29A002418
• Array T(n,m) = 2*(2m+3)!*(4n+2m+1)!/(m!*(m+2)!*n!*(3n+2m+3)!) read by antidiagonals.at n=37A146305
• a(n) = ((2^b-1)/phi(n))*Sum_{d|n} Moebius(n/d)*d^(b-1) for b = 5.at n=16A160894
• Numbers n such that sigma(n) = 13*phi(n) (where sigma=A000203, phi=A000010).at n=7A171258
• a(n) = (10 / ((3*n+1)*(3*n+2))) * binomial(4*n, n).at n=8A197271