A281902 Numbers n which have the form n = k^2 - k + (i^2-i)/2 + 2*k*i, k>=1, i>=0.

0, 2, 5, 6, 9, 11, 12, 14, 17, 19, 20, 24, 27, 29, 30, 32, 35, 36, 39, 41, 42, 44, 46, 50, 51, 53, 54, 55, 56, 57, 62, 65, 66, 69, 71, 72, 74, 75, 77, 80, 82, 84, 87, 89, 90, 95, 96, 100, 101, 104, 107, 109, 110, 111, 116, 117, 119, 120, 122, 126, 127, 128

Offset: 1

Author

Vladimir Shevelev, Feb 01 2017

Keywords

• nonn

Comments

If prime p has form 8*n+1, then n is a member.

Links

• Peter J. C. Moses, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A007519.

Formula

8k^2+8n+1 is perfect square.

Extensions

More terms from Peter J. C. Moses, Feb 01 2017