61620

Appears in sequences

• a(n) is both the sum of n+1 consecutive integers and the sum of the n immediately higher consecutive integers.at n=39A059270
• Number of 2 X 2 matrices with all elements in {0,1,...,n} and positive even determinant.at n=20A210372
• Numbers k such that psi(k^2) = k, psi = A002322; indices of 1 in A341857.at n=43A341858