cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A335650 Numbers that are multiples of 2,3,5, or 7 but not multiples of the product of any combination of 2,3,5, and 7.

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%I A335650 #28 Jul 08 2020 14:24:24
%S A335650 2,3,4,5,7,8,9,16,22,25,26,27,32,33,34,38,39,44,46,49,51,52,55,57,58,
%T A335650 62,64,65,68,69,74,76,77,81,82,85,86,87,88,91,92,93,94,95,99,104,106,
%U A335650 111,115,116,117,118,119,122,123,124,125,128,129,133,134,136,141,142
%N A335650 Numbers that are multiples of 2,3,5, or 7 but not multiples of the product of any combination of 2,3,5, and 7.
%e A335650 4 is a term because 4 = 2 * 2;
%e A335650 77 is a term because 77 = 7 * 11;
%e A335650 6 is not a term because 6 = 2 * 3;
%e A335650 21 is not a term because 21 = 3 * 7;
%e A335650 30 is not a term because 30 = 2 * 3 * 5;
%e A335650 210 is not a term because 210 = 2 * 3 * 5 * 7.
%p A335650 q:= n-> is(igcd(n, 210) in {2,3,5,7}):
%p A335650 select(q, [$0..200])[];  # _Alois P. Heinz_, Jun 16 2020
%t A335650 Select[Range[150], Count[IntegerExponent[#, {2, 3, 5, 7}], 0] == 3 &] (* _Amiram Eldar_, Jun 16 2020 *)
%o A335650 (Haskell) a335650 = [x | x <- [0..], (gcd x 210) `elem` [2,3,5,7]]
%Y A335650 Cf. A126590.
%K A335650 nonn
%O A335650 1,1
%A A335650 _Peter Andrew_, Jun 15 2020