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 A117112 Primes expressible as the sum of two triangular numbers (including zero). 7
 2, 3, 7, 11, 13, 29, 31, 37, 43, 61, 67, 73, 79, 83, 97, 101, 127, 137, 139, 151, 157, 163, 181, 191, 193, 199, 211, 227, 241, 263, 277, 281, 307, 331, 353, 367, 373, 379, 389, 409, 421, 433, 443, 461, 463, 487, 499, 541, 571, 577, 587, 601, 619, 631, 659, 661 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS See A117048 for the primes that are the sum of two positive triangular numbers. The only difference is that the prime 3 occurs here. LINKS FORMULA A000040 intersect A020756. - Jonathan Vos Post, Apr 17 2006 EXAMPLE 2 = 1 + 1 3 = 0 + 3 7 = 1 + 6 and so on. MATHEMATICA tri = Table[n (n + 1)/2, {n, 0, 40}]; Select[Union[Flatten[Outer[Plus, tri, tri]]], # <= tri[[-1]]+1 && PrimeQ[#] &] (* T. D. Noe, Apr 07 2011 *) Select[Total/@Tuples[Accumulate[Range[0, 40]], 2], PrimeQ]//Union (* Harvey P. Dale, Apr 21 2019 *) CROSSREFS Cf. A000217, A117048. Sequence in context: A091206 A038963 A167609 * A145032 A233414 A233863 Adjacent sequences:  A117109 A117110 A117111 * A117113 A117114 A117115 KEYWORD easy,nonn AUTHOR Greg Huber, Apr 18 2006 STATUS approved

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Last modified March 30 12:10 EDT 2020. Contains 333125 sequences. (Running on oeis4.)