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A176171 Second prime-factor of n-th product of 4 distinct primes. 2
3, 3, 3, 3, 3, 3, 3, 3, 3, 5, 3, 3, 3, 5, 3, 3, 3, 3, 5, 5, 3, 3, 3, 3, 3, 3, 5, 5, 3, 5, 3, 3, 3, 3, 5, 3, 3, 5, 3, 3, 3, 5, 3, 3, 3, 5, 7, 3, 5, 3, 5, 3, 5, 5, 3, 5, 3, 3, 3, 3, 5, 3, 3, 5, 3, 3, 5, 3, 5, 7, 3, 3, 3, 5, 3, 3, 5, 3, 3, 7, 3, 3, 5, 7, 5, 3, 5, 3, 3, 7, 3, 5, 3, 5, 3, 3, 5, 5, 3, 5, 3, 5, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

FactorInteger[210]=2*3*5*7,...

LINKS

Table of n, a(n) for n=1..105.

MATHEMATICA

f0[n_]:=Last/@FactorInteger[n]=={1, 1, 1, 1}; f1[n_]:=Min[First/@FactorInteger[n]]; f2[n_]:=First/@FactorInteger[n][[2, 1]]; f3[n_]:=First/@FactorInteger[n][[3, 1]]; f4[n_]:=Max[First/@FactorInteger[n]]; lst={}; Do[If[f0[n], AppendTo[lst, f2[n]]], {n, 0, 2*7!}]; lst

CROSSREFS

Cf. A006881, A007304, A070647, A096916, A096917, A096918, A096919, A176170

Sequence in context: A243129 A135717 A079083 * A032568 A053388 A091786

Adjacent sequences:  A176168 A176169 A176170 * A176172 A176173 A176174

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Apr 10 2010

STATUS

approved

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Last modified March 28 07:59 EDT 2020. Contains 333079 sequences. (Running on oeis4.)