OFFSET
2,1
COMMENTS
If the requirement that m be an element of A173977 is dropped, the sequence becomes A006254. - R. J. Mathar, Nov 02 2011
LINKS
Amiram Eldar, Table of n, a(n) for n = 2..1000
MAPLE
A020639 := proc(n) if n = 1 then 1; else min(op(numtheory[factorset](n)) ) ; end if; end proc:
A173979 := proc(n) local p, m ; p := ithprime(n) ; for m from 1 do if A020639(2*m-1) = p and isA173977(m) then return m ; end if; end do: end proc:
seq(A173979(n), n=2..40) ; # R. J. Mathar, Sep 02 2011
MATHEMATICA
lpf[n_] := lpf[n] = FactorInteger[n][[1, 1]]; q[n_] := lpf[2*n-1] < lpf[2*n-3]; seq[len_] := Module[{s = Table[0, {Prime[len+1]}], k = 2, c = 0, p}, While[c < len, If[q[k], p = lpf[2*k-1]; If[p <= Length[s] && s[[p]] == 0, c++; s[[p]] = k]]; k++]; Select[s, # > 0 &]]; seq[100] (* Amiram Eldar, Oct 25 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Mar 04 2010
EXTENSIONS
Name corrected by Vladimir Shevelev, Mar 15 2010
STATUS
approved