18131

Properties

Appears in sequences

• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 88 ones.at n=21A031856
• Smallest prime p having n different cycles in decimal expansions of k/p, k=1..p-1.at n=36A054471
• Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 23 (most significant digit on right).at n=7A061976
• Numbers k such that sigma(k+2) - sigma(k) = prime(k+1) - prime(k).at n=39A067062
• Square-chain primes (including square-loop primes).at n=35A108659
• Denominators of convergents to 1 + 2/(3 + 4/(5 + 6/(7 + ...))).at n=5A113013
• Primes congruent to 5 mod 53.at n=37A142535
• Primes congruent to 14 mod 61.at n=32A142812
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, -1), (0, 1, -1), (0, 1, 1), (1, -1, -1)}.at n=10A148539
• Number of planar triangular n X n X n nonnegative integer grids with every similarly oriented 3 X 3 X 3 subtriangle summing to 6.at n=7A154056
• G.f.: (1+44*x+339*x^2+630*x^3+323*x^4+42*x^5+x^6)/(1-x)^7.at n=4A160835
• Primes p of the form 4*k+3 such that p+2 is prime and p-1 is nonsquarefree.at n=19A175606
• Prime-generating polynomial: a(n) = 16*n^2 - 300*n + 1447.at n=43A181973
• Number of partitions of n in which any two parts differ by at most 10.at n=39A218512
• Primes p with p + 2 and prime(p) + 2 both prime.at n=36A236458
• Primes p such that (2*p)^3 + 1 is a semiprime.at n=46A237038
• Primes p such that p1 = ceiling(p/2) + p is prime and p2 = floor(p1/2) + p is prime.at n=37A242366
• Number of (n+1) X (1+1) 0..2 arrays with nondecreasing x(i,j)+x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.at n=6A250625
• T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with nondecreasing x(i,j)+x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.at n=27A250632
• Number of (7+1)X(n+1) 0..2 arrays with nondecreasing x(i,j)+x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.at n=0A250639