cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A227348 Nonsquarefree integers m such that, for prime p, if p^k | m then 1+p^k | 1+m.

Original entry on oeis.org

26999, 122499, 193599, 599975, 2206775, 2620175, 3501575, 4798079, 8278599, 11631059, 14242175, 16956575, 17578799, 19048799, 49061375, 55504175, 57354725, 70963775, 75271559, 107499699, 114930639, 153536525, 165887189, 202729175, 241430399, 248688719, 257552735, 258969887, 275089919
Offset: 1

Views

Author

Emmanuel Vantieghem, Jul 08 2013

Keywords

Comments

The sequence is part of A056729.
All members are odd.

Examples

			26999 = 49*19*29 is in the list because 27000 is divisible by 8,50,20 and 30;
193599 = 9*49*439 is in the list because 193600 is divisible by 4,10,8, 50,440.
		

Crossrefs

Cf. A056729.

Programs

  • Mathematica
    PPDivs[m_Integer]:=Module[{f=FactorInteger[m]},Flatten[Table[First[f[[i]]]^Range[Last[f[[i]]]],{i,1,Length[f]}]]]; Select[Select[ Range[1000000], !SquareFreeQ[#]&], Union[ Mod[#+1, 1+PPDivs[#] ] ]== {0} &]