21772

Appears in sequences

• Sum of primes in n-th shell of prime spiral.at n=5A053997
• Number of 2 X 2 matrices having all terms in {-n,...,0,...,n} and determinant n-1.at n=33A211141
• Positive integers m such that none of the four consecutive numbers m, m+1, m+2, m+3 can be written as p^2 + q with p and q both prime.at n=12A258661
• Number of n X n arrays containing n copies of 0..n-1 with every element equal to or 1 greater than any north or northeast neighbors modulo n and the upper left element equal to 0.at n=7A267552
• Number of nonnegative solutions to (x_1)^2 + (x_2)^2 + ... + (x_8)^2 <= n.at n=22A341403
• Numbers t which satisfy the equation: t mod k = floor((t - k)/k) mod k (1 <= k <= t) only for k = 1 and t.at n=24A375007