26820

Appears in sequences

• Numbers k such that 4*k-1, 8*k-1, 16*k-1 and 32*k-1 are all primes.at n=15A101794
• Triangle, read by rows, equal to the matrix cube of triangle A113389.at n=17A113394
• Numbers n for which 2n-1, 4n-1, 8n-1, 16n-1 and 32n-1 are primes.at n=2A124017
• Numbers k for which 2*k-1, 4*k-1, 8*k-1 and 16*k-1 are primes.at n=22A124494
• Number of 11 X 11 arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to n.at n=2A156406
• Number of n X n arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 2.at n=9A156430
• a(n) = Hermite(n, 15).at n=3A158580
• The 3rd Hermite Polynomial evaluated at n: H_3(n) = 8*n^3 - 12*n.at n=15A163322
• Numbers m = Sum_{k=1..n} sigma(k) such that Sum_{k=1..n} sigma(k) is divisible by k.at n=6A168133
• Expansion of 1/(1 - x - x^2 + x^6 - x^8).at n=23A225393
• Smallest number k such that prime(n) divides the n-th divisor of k.at n=33A226101
• Expansion of Product_{k>=1} (1 - x^(5*k))^(5*k) / (1 - x^k)^k.at n=19A285246
• Numbers k such that sigma(k) AND 3*k = 3*k, where AND is bitwise-and, A004198.at n=38A388022
• Primitive terms of A388022: numbers k that satisfy sigma(k) AND 3*k = 3*k, but none of whose proper divisors satisfy the same condition.at n=12A388025