42050

Appears in sequences

• a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 4, with initial terms 1,-1,1.at n=16A025267
• Numbers that are the sum of 2 nonzero squares in exactly 5 ways.at n=14A025288
• Numbers k such that phi(k)^2+sigma(k)^2 is prime.at n=31A068367
• Numbers n that are the hypotenuse of exactly 12 distinct integer-sided right triangles, i.e., n^2 can be written as a sum of two squares in 12 ways.at n=15A097226
• Number of 0..7 arrays x(0..n+1) of n+2 elements with zero n-1st differences.at n=21A200271
• Triangle read by rows: T(n,k) is the number of permutations of [1..n] with k modular progressions of rise 2, distance 1 and length 3 (n >= 0, k >= 0).at n=37A216724
• Numbers that are multiple-digit narcissistic numbers in exactly four bases.at n=5A256363
• Numbers that are the sum of 2 squares in exactly 5 ways.at n=22A294716