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A242058
Even numbers n for which lpf_3(n-1) > lpf_3(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.
5
6, 8, 12, 14, 18, 20, 24, 30, 32, 38, 42, 44, 48, 52, 54, 58, 60, 62, 68, 72, 74, 78, 80, 84, 88, 90, 94, 98, 102, 104, 108, 110, 114, 118, 122, 124, 128, 132, 138, 140, 148, 150, 152, 158, 164, 168, 172, 174, 178, 180, 182, 188, 192, 194, 198, 200, 208, 212
OFFSET
1,1
COMMENTS
An analog of A243937.
LINKS
MATHEMATICA
lpf[n_]:=lpf[n]=First[First[FactorInteger[n]]];
lpf3[n_]:=lpf3[n]=If[#==1, 1, lpf[#]]&[n/3^IntegerExponent[n, 3]]
Select[Range[4, 300, 2], lpf3[#-1]>lpf3[#-3]&] (* Peter J. C. Moses, Aug 13 2014 *)
PROG
(PARI) lpf3(n)=m=n/3^valuation(n, 3); if(m>1, factor(m)[1, 1], 1)
select(n->lpf3(n-1)>lpf3(n-3), vector(200, x, 2*x)) \\ Jens Kruse Andersen, Aug 19 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Aug 13 2014
EXTENSIONS
More terms from Peter J. C. Moses, Aug 13 2014
STATUS
approved