A242060 - OEIS

A242060

Lpf_3(A242058(n)-3), where lpf_3(n) = lpf(n/3^t) (cf. A020639) such that 3^t (t>=0) is the maximal power of 3 which divides n.

1, 5, 1, 11, 5, 17, 7, 1, 29, 5, 13, 41, 5, 7, 17, 5, 19, 59, 5, 23, 71, 5, 7, 1, 5, 29, 7, 5, 11, 101, 5, 107, 37, 5, 7, 11, 5, 43, 5, 137, 5, 7, 149, 5, 7, 5, 13, 19, 5, 59, 179, 5, 7, 191, 5, 197, 5, 11, 5, 7, 13, 5, 227, 7, 5, 79, 239, 1, 5, 13, 83, 5, 7

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

OFFSET

1,2

COMMENTS

An analog of A242034. Records are lesser numbers of twin primes.

LINKS

Table of n, a(n) for n=1..73.

MATHEMATICA

lpf[n_]:=lpf[n]=First[First[FactorInteger[n]]];

lpf3[n_]:=lpf3[n]=If[#==1, 1, lpf[#]]&[n/3^IntegerExponent[n, 3]]

Map[lpf3[#-3]&, Select[Range[4, 300, 2], lpf3[#-1]>lpf3[#-3]&]](* Peter J. C. Moses, Aug 13 2014 *)

CROSSREFS