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 A171126 #24 Mar 29 2025 04:25:05 %S A171126 2,3,10,14,15,21,22,26,33,34,38,39,46,50,51,57,58,62,69,70,74,75,82, %T A171126 86,87,93,94,98,105,106,110,111,118,122,123,129,130,134,141,142,146, %U A171126 147,154,158,159,165,166,170,177,178,182,183,190,194,195,201,202,206,213 %N A171126 Numbers k such that A169611(k) = 1. %C A171126 Appears to be numbers k such that tau(36*k) = 2*tau(6*k). - _Gary Detlefs_, Jan 13 2020 %C A171126 The asymptotic density of this sequence is 5/18. - _Amiram Eldar_, Jan 16 2022 %C A171126 Numbers that have exactly two 3-smooth divisors, i.e., numbers k such that A072078(k) = 2. - _Amiram Eldar_, Mar 29 2025 %H A171126 Amiram Eldar, <a href="/A171126/b171126.txt">Table of n, a(n) for n = 1..10000</a> %t A171126 f[n_] := Plus @@ Last /@ Select[ FactorInteger@ n, 1 < #[[1]] < 4 &]; Select[ Range@ 213, f@# == 1 &] (* _Robert G. Wilson v_, Dec 19 2009 *) %o A171126 (PARI) isok(n) = valuation(n, 2)+valuation(n, 3) == 1; \\ _Michel Marcus_, Jan 13 2020 %Y A171126 Cf. A000005 (tau), A072078, A169611. %K A171126 nonn,easy %O A171126 1,1 %A A171126 _Juri-Stepan Gerasimov_, Dec 04 2009 %E A171126 More terms from _Robert G. Wilson v_, Dec 19 2009