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%I #12 Mar 05 2024 14:43:46
%S 11,13,29,31,137,139,191,193,461,463,659,661,821,823,1091,1093,1721,
%T 1723,2027,2029,2081,2083,2711,2713,3359,3361,3539,3541,3917,3919,
%U 6131,6133,6761,6763,7589,7591,7877,7879,7949,7951,8219,8221,9461,9463,9857
%N Twin-prime pairs expressible as the sum of two triangular numbers.
%H Amiram Eldar, <a href="/A117314/b117314.txt">Table of n, a(n) for n = 1..10000</a>
%e a(1) = 11 = 1 + 10; a(2) = 13 = 3 + 10.
%t 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 *)
%Y Cf. A117048, A117112, A118638.
%K easy,nonn
%O 1,1
%A _Greg Huber_, Apr 24 2006
%E More terms from _Robert G. Wilson v_, Apr 27 2006
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