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 A332971 #11 Mar 05 2020 03:43:42 %S A332971 3,4,7,23,121,2857,5699,6377,9179,46537,63209,244967,654497,1067873, %T A332971 1112009,3435929,3831257,6441593,7589737,7784507,8149751,14307856, %U A332971 22434089,24007727,24571871,44503417,44926463,56732729,128199059,140830367,190145936,401767631,403152737 %N A332971 Infinitary phibonacci numbers: solutions k of the equation iphi(k) = iphi(k-1) + iphi(k-2) where iphi(k) is an infinitary analog of Euler's phi function (A091732). %H A332971 Amiram Eldar, <a href="/A332971/b332971.txt">Table of n, a(n) for n = 1..70</a> %e A332971 7 is a term since iphi(7) = 6 and iphi(5) + iphi(6) = 4 + 2 = 6. %t A332971 f[p_, e_] := p^(2^(-1 + Position[Reverse@IntegerDigits[e, 2], 1])); iphi[1] = 1; iphi[n_] := Times @@ (Flatten @ (f @@@ FactorInteger[n]) - 1); Select[Range[3, 10^5], iphi[#] == iphi[# - 1] + iphi[# - 2] &] %Y A332971 An infinitary version of A065557. %Y A332971 Cf. A065900, A075565, A076136, A076251, A091732, A145469, A291126, A291176, A292033, A294995. %K A332971 nonn %O A332971 1,1 %A A332971 _Amiram Eldar_, Mar 04 2020