id:A152900 - OEIS Search Results

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Primes p such that there exists a triangular number t with p*t also triangular.

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2, 3, 5, 7, 11, 13, 19, 23, 29, 31, 41, 43, 53, 71, 73, 89, 109, 127, 131, 157, 163, 181, 211, 233, 239, 241, 271, 281, 307, 379, 419, 421, 431, 461, 463, 541, 599, 601, 613, 701, 743, 757, 811, 827, 929, 977, 991, 1123, 1259, 1481, 1483, 1559, 1721, 1723 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`Sequence A152899 contains the triangular numbers t.`
	LINKS	`T. D. Noe, Table of n, a(n) for n=1..1000`
	EXAMPLE	`11 is here because 21 and 11*21 are triangular.`
	MATHEMATICA	`TriQ[n_]:=IntegerQ[Sqrt[1+8n]]; Select[Prime[Range[1000]], TriQ[2#-1] \|\| TriQ[2#+1] \|\| TriQ[(#-1)/2] \|\| TriQ[(#+1)/2] &]`
	CROSSREFS	`A000217` `Sequence in context: A097375 A007459 A129944 this_sequence A079151 A005728 A049643` `Adjacent sequences: A152897 A152898 A152899 this_sequence A152901 A152902 A152903`
	KEYWORD	`nonn`
	AUTHOR	`T. D. Noe (noe(AT)sspectra.com), Dec 14 2008`

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Last modified December 9 18:50 EST 2009. Contains 170568 sequences.

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