A217920 Column 1 of A217916 (when formed into a number triangle).

2, 1, 2, 4, 2, 6, 6, 2, 6, 2, 6, 14, 4, 12, 6, 2, 4, 4, 2, 2, 6, 6, 2, 4, 6, 8, 6, 16, 6, 4, 6, 6, 6, 6, 6, 6, 14, 6, 6, 14, 10, 10, 8, 4, 12, 20, 8, 12, 6, 10, 2, 6, 14, 2, 14, 18, 6, 2, 6, 12, 4, 28, 6, 20, 6, 6, 6, 4, 16, 2, 2, 6, 4, 12, 6, 6, 6, 6, 8, 4, 6, 8, 6

Offset

1,1

Comments

The number 2 appears in A217916 only in column 1.

The positions of 2 are given by A217919.

Links

Paul D. Hanna, Table of n, a(n) for n = 1..287

Formula

a(n) = prime(n*(n-1)/2 + 1) - prime(n*(n-1)/2) for n>1 with a(1)=2.

Crossrefs

Cf. A217916, A217918, A217919.

Sequence in context: A079878 A324469 A329688 * A137406 A181293 A262876

Adjacent sequences: A217917 A217918 A217919 * A217921 A217922 A217923

Keyword

nonn

Author

Paul D. Hanna, Mar 04 2013

Status

approved