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.

A074970 Number of steps to reach the first integer starting with sigma(n)/n and iterating the map x -> x*ceiling(x), or -1 if no integer is ever reached.

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%I A074970 #8 Jan 16 2022 11:08:25
%S A074970 0,1,2,2,18,0,3,2,3,3,26,1,9,3,7,3,6,3,56,10,9,15,42,2,10,3,3,0,38,17,
%T A074970 79,3,27,16,8,8,200,76,4,3,36,2,4,15,4,51,11,2,4,6,22,42,43,5,25,2,4,
%U A074970 103,37,17,18,20,8,3,22,25,225,59,6,13,20,4,182,13,8
%N A074970 Number of steps to reach the first integer starting with sigma(n)/n and iterating the map x -> x*ceiling(x), or -1 if no integer is ever reached.
%C A074970 a(p) = A073524(p) for primes p.
%e A074970 a(26)=3 since (26+13+2+1)/26=21/13 -> 42/13 -> 168/13 -> 168.
%Y A074970 Cf. A000203, A009194, A073524.
%K A074970 nonn
%O A074970 1,3
%A A074970 _Reinhard Zumkeller_, Oct 05 2002
%E A074970 a(20) corrected by and more terms from _Jinyuan Wang_, Jan 15 2022