18088

Appears in sequences

• Coordination sequence for hyperbolic tessellation 3^7 (from triangle group (2,3,7)).at n=9A001354
• Fibonacci sequence beginning 0, 7.at n=18A022090
• Dying rabbits: a(n) = a(n-1) + a(n-2) - a(n-6).at n=24A023436
• Perimeters of more than one primitive Pythagorean triangle.at n=32A024408
• a(n) = Sum_{k=0..2n-1} T(n,k) * T(n,k+1), with T given by A027023.at n=5A027047
• Smallest number with persistence n for the sort-and-subtract-sequence.at n=21A065641
• a(n) = (3*n+1)*(3*n+4).at n=44A085001
• Sixth column of (1,5)-Pascal triangle A096940.at n=13A096943
• Numbers which are the sum of two positive cubes and divisible by 17.at n=17A099178
• Numbers n such that sigma(n)/phi(n) = 25/4, where sigma = A000203, phi = A000010.at n=2A165629
• Numbers that take a record number of steps to appear in A181391.at n=48A171863
• Number of (n+3) X 6 binary arrays with every 4 X 4 subblock commuting with each horizontal and vertical neighbor 4 X 4 subblock.at n=14A188099
• a(n) = gcd(Sum_{k=1...n} F(k), Product{j=1...n} F(j)), where F(k) is the k-th Fibonacci number.at n=35A239740
• Number of length 5 1..(n+1) arrays with every leading partial sum divisible by 2, 3, 5, 7 or 11.at n=7A254952
• Number of ways to select a subset s from an n-set and then partition s into blocks of equal size.at n=10A262320
• Numbers k such that k and k+2 are both infinitary practical numbers (A334901).at n=38A334903
• Number of compositions of n whose distinct parts are pairwise coprime, where a singleton is not considered coprime unless it is (1).at n=16A337665
• Total number of 1's in the binary expansion of parts in all partitions of n into distinct parts.at n=44A347060
• a(n) = 840*(2*n)!/((n + 4)!*n!).at n=11A348893
• Least number k such that k and k+2 both have exactly 2n divisors, or -1 if no such number exists.at n=15A356766