This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A115882 Numbers n such that n plus the n-th prime gives a triangular number. 6
 1, 20, 49, 65, 103, 176, 279, 284, 299, 437, 513, 553, 656, 973, 1271, 1779, 1921, 2156, 2312, 2347, 2554, 2759, 3176, 3379, 4008, 4028, 4132, 5255, 6354, 6764, 7116, 8299, 8334, 8366, 8723, 9277, 9755, 10092, 10475, 10631, 11429, 11842, 12633, 13157, 13627 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS T. D. Noe, Table of n, a(n) for n = 1..1000 EXAMPLE 103+prime(103)=103+563=666=T(36). MATHEMATICA TriangularQ[n_] := IntegerQ[Sqrt[1 + 8*n]]; Select[Range[20000], TriangularQ[# + Prime[#]] &] (* T. D. Noe, Jan 27 2014 *) PROG (PARI) isok(n) = ispolygonal(n + prime(n), 3); \\ Michel Marcus, Jan 25 2014 CROSSREFS Cf. A064371, A115883, A115886. Sequence in context: A177725 A264444 A053245 * A303295 A277553 A260093 Adjacent sequences:  A115879 A115880 A115881 * A115883 A115884 A115885 KEYWORD nonn AUTHOR Giovanni Resta, Feb 06 2006 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 16 05:41 EDT 2019. Contains 328044 sequences. (Running on oeis4.)