# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a335327 Showing 1-1 of 1 %I A335327 #5 Jun 01 2020 20:46:13 %S A335327 1,2,6,12,24,72,120,240,480,1440,2880,5760,8640,17280,65280,86400, %T A335327 120960,130560,259200,391680,783360,1566720,2350080,4700160,23500800, %U A335327 32901120,47001600,70502400,94003200,470016000,1410048000,2820096000,4294901760,5640192000,8460288000 %N A335327 Numbers k such that iphi(k) divides k, where iphi is an infinitary analog of Euler's phi function (A091732). %e A335327 6 is a term since iphi(6) = 2 is a divisor of 6. %t A335327 f[p_, e_] := p^(2^(-1 + Position[Reverse @ IntegerDigits[e, 2], 1])); a[1] = 1; iphi[n_] := Times @@ (Flatten@(f @@@ FactorInteger[n]) - 1); Select[Range[10^5], Divisible[#,a[#]] &] %Y A335327 Cf. A007694, A091732, A319481. %K A335327 nonn %O A335327 1,2 %A A335327 _Amiram Eldar_, Jun 01 2020 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE