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A131931 Smallest number containing exactly n prime factors in its decimal representation. 2

%I #8 Sep 08 2018 03:11:13

%S 1,2,132,735,21372,271362,4773132,113678565,11317129824

%N Smallest number containing exactly n prime factors in its decimal representation.

%C A131929(a(n)) = n and A131929(m) <> n for m<a(n).

%e a(2) = 2^2 * 3 * 11 = 132 containing 2 and 3;

%e a(3) = 3 * 5 * 7^2 = 735 containing 3, 5 and 7;

%e a(4) = 2^2 * 3 * 13 * 137 = 21372 containing 2, 3, 13 and 137;

%e a(5) = 2 * 3 * 7^2 * 13 * 71 = 271362 containing 2, 3, 7, 13 and 71.

%Y Cf. A131930, A131929, A318965.

%K nonn,base,more

%O 0,2

%A _Reinhard Zumkeller_, Jul 30 2007

%E Offset changed by and a(6)-a(8) from _Giovanni Resta_, Sep 06 2018

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Last modified June 14 04:49 EDT 2024. Contains 373393 sequences. (Running on oeis4.)