42787

Properties

Appears in sequences

• Number of n X n integer matrices, symmetric under 180 degree rotation, with adjacent elements differing by no more than 1, counting matrices differing by a constant only once.at n=4A141445
• Primes p such that continued fraction of (1 + sqrt(p))/2 has period 14: primes in A146337.at n=20A146359
• Number of nX2 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4.at n=12A241392
• a(1) = 1, a(2) = 0; for n >= 3, a(n) = least number not included earlier that divides the concatenation of all previous terms.at n=38A241811
• The first of 23 consecutive positive integers the sum of the squares of which is a square.at n=4A269447
• Primes for which the sum of all preceding odd-indexed prime gaps is exactly one greater than the sum of all preceding even-indexed prime gaps.at n=30A282178
• Primes p such that 6p - 1 and 6p + 1 are twin primes and ((6p-1)^2 + (6p+1)^2) / 10 is prime.at n=27A283957
• Number T(n,k) of proper k-times partitions of n; triangle T(n,k), n >= 0, 0 <= k <= max(0,n-1), read by rows.at n=50A327639
• Union of 2, A282178, and A330339.at n=42A330554
• Primes that are palindromic in factorial base.at n=31A333421
• Primes that do not divide any 3-Carmichael numbers.at n=32A369777
• Prime numbersat n=4474