A117314 Twin-prime pairs expressible as the sum of two triangular numbers.

11, 13, 29, 31, 137, 139, 191, 193, 461, 463, 659, 661, 821, 823, 1091, 1093, 1721, 1723, 2027, 2029, 2081, 2083, 2711, 2713, 3359, 3361, 3539, 3541, 3917, 3919, 6131, 6133, 6761, 6763, 7589, 7591, 7877, 7879, 7949, 7951, 8219, 8221, 9461, 9463, 9857

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

a(1) = 11 = 1 + 10; a(2) = 13 = 3 + 10.

Mathematica

s = Select[Union@ Flatten@ Table[i(i + 1)/2 + j(j + 1)/2, {i, 200}, {j, 0, i}], PrimeQ@ # &]; t = Select[Range@Length@s - 1, s[[ # ]] + 2 == s[[ # + 1]] &]; Sort@Join[s[[t]], s[[t + 1]]] (* Robert G. Wilson v, Apr 27 2006 *)

Crossrefs

Cf. A117048, A117112, A118638.

Sequence in context: A132245 A140567 A232880 * A115560 A045466 A158759

Adjacent sequences: A117311 A117312 A117313 * A117315 A117316 A117317

Keyword

easy,nonn

Author

Greg Huber, Apr 24 2006

Extensions

More terms from Robert G. Wilson v, Apr 27 2006

Status

approved