A217919 Rows of A217916 in which 2's appear, when A217916 is formed into a number triangle.

1, 3, 5, 8, 10, 16, 19, 20, 23, 51, 54, 58, 70, 71, 103, 136, 139, 142, 145, 153, 161, 168, 169, 182, 204, 212, 219, 222, 224, 230, 232, 235, 240, 242, 276, 277, 286

Offset

1,2

Comments

The number 2 appears only in column 1 of A217916 (when treated as a triangle).

Links

Table of n, a(n) for n=1..37.

Formula

Involves triangular-indexed twin primes:

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

Crossrefs

Cf. A217916, A217918.

Sequence in context: A133097 A117176 A212987 * A127700 A101907 A242250

Adjacent sequences: A217916 A217917 A217918 * A217920 A217921 A217922

Keyword

nonn

Author

Paul D. Hanna, Mar 04 2013

Status

approved