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A152900 Primes p such that there exists a triangular number t with p*t also triangular. 2
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; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Sequence A152899 contains the triangular numbers t.
LINKS
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
Sequence in context: A007459 A129944 A176162 * A079151 A274335 A049643
KEYWORD
nonn
AUTHOR
T. D. Noe, Dec 14 2008
STATUS
approved

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)