18591

Appears in sequences

• a(1) = 1; for n>1, a(n) = the smallest number p > a(n-1) such that (a(n-1)+p)/2 is a cube.at n=25A126950
• Numbers k such that 2^k - 1 - Sum_{prime p<k} 2^p is prime.at n=30A215888
• Triangle T(n, k) = Numbers of ways to place k points on a triangular grid of side n so that no three of them are vertices of an equilateral triangle with sides parallel to the grid. Triangle read by rows.at n=43A243211
• Number of ways to place 4 points on a triangular grid of side length n so that no three of them are vertices of an equilateral triangle with sides parallel to the grid.at n=4A243213
• Isolated deficient numbers that are divisible by 3.at n=27A273255
• a(n) is the minimum positive integer k such that the concatenation of k, a(n-1), a(n-2), ..., a(2), and a(1) is the lesser of a pair of twin primes (i.e., a term of A001359), with a(1) = 11.at n=28A350246