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 A119961 Semiprimes that are the sum of two triangular numbers. 0
 4, 6, 9, 10, 15, 21, 22, 25, 34, 38, 39, 46, 49, 51, 55, 57, 58, 65, 69, 87, 91, 93, 94, 106, 111, 115, 119, 121, 123, 133, 141, 142, 146, 159, 169, 177, 183, 202, 205, 213, 214, 218, 219, 226, 235, 237, 249, 253, 254, 259, 262, 265, 267, 274, 289, 291, 295 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Semiprime analog of A117048 Prime numbers that are expressible as the sum of two triangular numbers. LINKS Table of n, a(n) for n=1..57. FORMULA A020756 intersection A001358. MATHEMATICA With[{nn=60}, Take[Union[Select[Total/@Tuples[Accumulate[Range[0, nn]], 2], PrimeOmega[ #] ==2&]], nn]] (* Harvey P. Dale, Nov 04 2020 *) CROSSREFS Cf. A001358, A020756, A117048. Sequence in context: A084662 A137167 A181564 * A122492 A178378 A133234 Adjacent sequences: A119958 A119959 A119960 * A119962 A119963 A119964 KEYWORD easy,nonn AUTHOR Jonathan Vos Post, Aug 02 2006 EXTENSIONS Missing a(2) and a(19)-a(53) from Giovanni Resta, Jun 13 2016 STATUS approved

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Last modified September 12 20:35 EDT 2024. Contains 375854 sequences. (Running on oeis4.)