Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A125770
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A125770 First occurrence of in A125769. +0
3
1, 2, 7, 9, 34, 31, 54, 15, 16, 26, 148, 68, 398, 62, 193, 25, 27, 140, 550, 397, 107, 113, 50, 122, 950, 226, 38, 169, 40, 562, 187, 44, 327, 763, 70, 211, 362, 49, 1726, 79, 394, 153, 55, 202, 1600, 125, 61, 419, 94, 95, 225, 98, 66, 1036, 508, 1298, 983, 69, 71 (list; graph; listen)
OFFSET

1,2

COMMENT

If we restrict ourselves to just j*T_k +1 or j*T_k -1 then there are vaulues which do not occur. As an example if the minus is used then 8&9 are missing.

MATHEMATICA

triQ[n_] := IntegerQ@ Sqrt[8*n + 1]; f[n_] := Block[{j = 1, p = Prime@n}, While[ !triQ[(p - 1)/j] && !triQ[(p + 1)/j], j++ ]; j]; t = Table[0, {100}]; Do[ a = f@n; If[a < 101 && t[[a]] == 0, t[[a]] = n; Print[{a, n}]], {n, 3500}]; t

CROSSREFS

A125769 = a(n) is the least number j such that j*T_k +/- 1 is n-th prime for some k-th triangular number.

Cf. A000217, A125765, A125766, A125767, A125768, A125769.

Sequence in context: A033855 A082007 A126871 this_sequence A042063 A041717 A002353

Adjacent sequences: A125767 A125768 A125769 this_sequence A125771 A125772 A125773

KEYWORD

nonn

AUTHOR

Jonathan Vos Post (jvospost2(AT)yahoo.com) & Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 03 2006

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified September 7 15:18 EDT 2008. Contains 143483 sequences.


AT&T Labs Research