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Search: id:A117314
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| A117314 |
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Twin-prime pairs expressible as the sum of two triangular numbers. |
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+0
2
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| 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
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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a(1) = 11 = 1 + 10; a(2) = 13 = 3 + 10.
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MATHEMATICA
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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 (rgwv(at)rgwv.com), Apr 27 2006
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CROSSREFS
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Cf. A117048, A117112.
Sequence in context: A090433 A022325 A132245 this_sequence A140567 A115560 A045466
Adjacent sequences: A117311 A117312 A117313 this_sequence A117315 A117316 A117317
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KEYWORD
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easy,nonn
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AUTHOR
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Greg Huber (huber(AT)alum.mit.edu), Apr 24 2006
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(at)rgwv.com), Apr 27 2006
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