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 A072011 #9 Dec 23 2019 06:02:52 %S A072011 1,2,4,8,16,32,35,64,70,128,140,256,280,323,512,560,646,899,1024,1120, %T A072011 1225,1292,1763,1798,2048,2240,2450,2584,3526,3596,4096,4480,4900, %U A072011 5168,7052,7192,8192,8960,9800,10336,10403,11305 %N A072011 Numbers k such that A072010(k) = k. %C A072011 If A072010(n) = n then also A072010(n*3^i) = n and A072010(n*2^j) = n*2^j. %C A072011 For m=(4*k+1)*(4*k+3), product of twin prime pairs: A072010(m) = m, as well as for values m in the free monoid generated by the range of A071697. %H A072011 Amiram Eldar, <a href="/A072011/b072011.txt">Table of n, a(n) for n = 1..5000</a> %e A072011 395675 is a term as f(395675) = f(323*1225) = f((17*19)*(5*7)^2) = f(17*19)*(f(5*7))^2 = f(17)*f(19)*(f(5)*f(7))^2 = 19*17*(7*5)^2 = 323*1225 = 395675 for f = A072010. %Y A072011 Cf. A002144, A002145, A071695, A071696, A071697, A072010. %K A072011 nonn %O A072011 1,2 %A A072011 _Reinhard Zumkeller_, Jun 05 2002