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.
%I A376881 #24 Oct 27 2024 11:47:03 %S A376881 6,18,20,28,70,88,100,104,196,272,304,368,464,496,550,572,650,836,945, %T A376881 968,1184,1312,1352,1376,1430,1504,1575,1696,1870,1888,1952,2002,2090, %U A376881 2205,2210,2470,2530,2584,2990,3128,3190,3230,3410,3465,3496,3770,3944 %N A376881 Numbers that have exactly one Zumkeller divisor. %C A376881 d is a Zumkeller divisor of n if and only if d is a divisor of n and is Zumkeller (A083207). %H A376881 Michael S. Branicky, <a href="/A376881/b376881.txt">Table of n, a(n) for n = 1..10000</a> %F A376881 If d is the only Zumkeller divisor of n and n is Zumkeller then d = n. %p A376881 # The function 'isZumkeller' is defined in A376880. %p A376881 zdiv := n -> select(isZumkeller, NumberTheory:-Divisors(n)): %p A376881 select(n -> nops(zdiv(n)) = 1, [seq(1..4000)]); %Y A376881 Subsequence of A376880. %Y A376881 Cf. A083207, A376877, A376882, A023196, A171641. %K A376881 nonn %O A376881 1,1 %A A376881 _Peter Luschny_, Oct 19 2024