cp's OEIS Frontend

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.

A048133 Least number which becomes prime or 4 after exactly n iterations of f(x) = sum of prime factors of x.

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%I A048133 #13 Dec 02 2024 18:13:33
%S A048133 2,6,8,14,26,62,134,393,1257,4659,9314,27933,167073,334142,4677862,
%T A048133 14033577,56134292,2133102298,11788191218,52541651594,536226160966,
%U A048133 2681130804805,8512643845707,129535245187539
%N A048133 Least number which becomes prime or 4 after exactly n iterations of f(x) = sum of prime factors of x.
%C A048133 f(x) = sum of prime factors with multiplicity, so that f(1500) = 2+2+3+5+5+5 = 22.
%C A048133 Identical to the different-offset A121360 except for the second term. - _Hans Havermann_, Oct 05 2010
%C A048133 a(20) <= 536226160966. a(21) <= 2681130804805. a(22) <= 8512643845707. - _Donovan Johnson_, Oct 16 2010
%C A048133 a(24) <= 1679460336114602. - _Danila Potapov_, Dec 01 2024
%Y A048133 Cf. A121360 .
%K A048133 nonn,more
%O A048133 0,1
%A A048133 _David W. Wilson_
%E A048133 a(17) from _Donovan Johnson_, Apr 25 2010
%E A048133 a(18)-a(19) from _Donovan Johnson_, Oct 16 2010
%E A048133 a(20)-a(23) from _Danila Potapov_, Dec 01 2024