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%I #21 Jun 23 2018 05:55:54
%S 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,
%T 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,
%U 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
%N a(n) = (smallest prime factor of n) * (least prime that is not a factor of n), with a(1)=2.
%H Robert Israel, <a href="/A096014/b096014.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A020639(n)*A053669(n);
%F A096015(n) = a(n)/2.
%F 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
%p f:= proc(n) local p;
%p p:= 3;
%p if n::even then
%p while type(n/p,integer) do p:= nextprime(p) od;
%p else
%p while not type(n/p,integer) do p:= nextprime(p) od:
%p fi;
%p 2*p;
%p end proc:
%p f(1):= 2:
%p map(f, [$1..100]); # _Robert Israel_, Jun 22 2018
%t 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 *)
%o (PARI) dnd(n) = forprime(p=2, , if (n % p, return(p)));
%o lpf(n) = if (n==1, 1, forprime(p=2, , if (!(n % p), return(p))));
%o a(n) = dnd(n)*lpf(n); \\ _Michel Marcus_, Jun 22 2018
%Y Cf. A020639, A053669, A096015.
%K nonn,look
%O 1,1
%A _Reinhard Zumkeller_, Jun 15 2004
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