A227348 - OEIS

A227348

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

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

The sequence is part of A056729.

All members are odd.

LINKS

Table of n, a(n) for n=1..29.

EXAMPLE

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.

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} &]

CROSSREFS

Cf. A056729.

Sequence in context: A048921 A269115 A249496 * A176359 A162144 A305728

Adjacent sequences: A227345 A227346 A227347 * A227349 A227350 A227351

KEYWORD

nonn

AUTHOR

Emmanuel Vantieghem, Jul 08 2013

STATUS

approved