83040

Appears in sequences

• a(n) = T(n,n-6), array T as in A055807.at n=18A055811
• Theta series of direct sum of 2 copies of 4-dimensional lattice QQF.4.i.at n=22A212817
• a(n) is the smallest k such that the following are four primes: prime(n)*k-1, prime(n)*k+1, prime(n)*k^2-1, prime(n)*k^2+1. Or -1 if no such k exists.at n=49A266239
• Number of regions formed by drawing the lines connecting any two of the 2*(n+2) perimeter points of a 3 X (n+1) rectangular grid of points (or equally, a 2 X n grid of squares).at n=23A331766
• Triangle read by rows: Take a hexagram with all diagonals drawn, as in A331908. Then T(n,k) = number of k-sided polygons in that figure for k = 3, 4, ..., n+5.at n=22A331909