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.

A343904 Composite numbers k such that k is divisible by A318996(k).

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%I A343904 #10 May 03 2021 18:39:50
%S A343904 4,45,304,464,1870,6048,14421,119072,130304,561824,1736150,8124416,
%T A343904 9519296,16303104,26409026
%N A343904 Composite numbers k such that k is divisible by A318996(k).
%e A343904 a(4) = 464 is a member because it is composite and is divisible by A318996(k) = 16.
%p A343904 filter:= proc(n) local D,s,d,v;
%p A343904   if isprime(n) then return false fi;
%p A343904 D:= numtheory:-divisors(n);
%p A343904 s:= convert(D,`+`);
%p A343904 v:= add(s mod d, d = D);
%p A343904   v > 0 and n mod v = 0
%p A343904 end proc:
%p A343904 select(filter, [$4..3*10^7]);
%Y A343904 Cf. A318996.
%K A343904 nonn,more
%O A343904 1,1
%A A343904 _J. M. Bergot_ and _Robert Israel_, May 03 2021