27674

Appears in sequences

• Composite numbers n such that sigma(n)+12 = sigma(n+12).at n=9A054902
• Numbers k such that 10*7^k + 1 is prime.at n=22A057437
• Irregular triangle read by rows: T(n,k) is the number of free polyaboloes (or polytans) with n cells of which 2*k share a hypotenuse in pairs (making up k squares), 0 <= k <= n/2.at n=54A391191
• Triangle read by rows: T(n,k) is the number of free polyaboloes (or polytans) with n cells (counted as in A390996) of which k are square cells consisting of two triangles sharing a hypotenuse, 0 <= k <= n.at n=41A391192