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 A096014 a(n) = (smallest prime factor of n) * (least prime that is not a factor of n), with a(1)=2. 6
 2, 6, 6, 6, 10, 10, 14, 6, 6, 6, 22, 10, 26, 6, 6, 6, 34, 10, 38, 6, 6, 6, 46, 10, 10, 6, 6, 6, 58, 14, 62, 6, 6, 6, 10, 10, 74, 6, 6, 6, 82, 10, 86, 6, 6, 6, 94, 10, 14, 6, 6, 6, 106, 10, 10, 6, 6, 6, 118, 14, 122, 6, 6, 6, 10, 10, 134, 6, 6, 6, 142, 10, 146, 6, 6, 6, 14, 10, 158, 6, 6, 6 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A020639(n)*A053669(n); A096015(n) = a(n)/2. If n (mod 6) = 2, 3 or 4, then a(n) = 6. If n (mod 6) = 0, 1 or 5, then a(n) belongs to A001747 less the first three terms or belongs to A073582 less the first two terms. - Robert G. Wilson v, Jun 15 2004 MAPLE f:= proc(n) local p; p:= 3; if n::even then   while type(n/p, integer) do p:= nextprime(p) od; else   while not type(n/p, integer) do p:= nextprime(p) od: fi; 2*p; end proc: f(1):= 2: map(f, [\$1..100]); # Robert Israel, Jun 22 2018 MATHEMATICA PrimeFactors[n_] := Flatten[ Table[ #[[1]], {1} ] & /@ FactorInteger[n]]; f[1] = 2; f[n_] := Block[ {k = 1}, While[ Mod[ n, Prime[k]] == 0, k++ ]; Prime[k]PrimeFactors[n][[1]]]; Table[ f[n], {n, 83}] (* Robert G. Wilson v, Jun 15 2004 *) PROG (PARI) dnd(n) = forprime(p=2, , if (n % p, return(p))); lpf(n) = if (n==1, 1, forprime(p=2, , if (!(n % p), return(p)))); a(n) = dnd(n)*lpf(n); \\ Michel Marcus, Jun 22 2018 CROSSREFS Cf. A020639, A053669, A096015. Sequence in context: A048765 A103643 A079892 * A071888 A117217 A260930 Adjacent sequences:  A096011 A096012 A096013 * A096015 A096016 A096017 KEYWORD nonn,look AUTHOR Reinhard Zumkeller, Jun 15 2004 STATUS approved

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Last modified January 17 10:25 EST 2021. Contains 340214 sequences. (Running on oeis4.)