A308125 - OEIS

%I #19 Aug 25 2021 06:58:36

%S 0,22,44,66,88,123,264,369,462,615,660,738,759,852,957,1120,1344,1568,

%T 1884,2024,2068,2200,2244,2288,2420,2464,2640,2684,2860,2912,3350,

%U 3360,3584,3752,4004,4048,4224,4268,4400,4444,4488,4620,4664,4840,4884,5024,6028,6204

%N Numbers k that are a multiple of the DENEAT operator applied to k (A073053).

%C The DENEAT operator is also known as the Sisyphus function.

%C On the other hand, the sequence of numbers k such that DENEAT(k) is a multiple of k, is the finite sequence {1, 11, 14, 16, 22, 56, 123}.

%D J. Schram, The Sisyphus string, J. Rec. Math., 19:1 (1987), 43-44.

%H Paolo P. Lava, <a href="/A308125/b308125.txt">Table of n, a(n) for n = 0..1000</a>

%e 2912 / DENEAT(2912) = 2912 / 224 = 13.

%p P:=proc(n) local a,b,c,d,k; a:=convert(n,base,10); b:=0: c:=0:

%p for k from 1 to nops(a) do if a[k] mod 2=0 then b:=b+1; else c:=c+1; fi;

%p od: d:=b*10^length(c)+c; a:=n/(d*10^length(length(n))+length(n)):

%p if frac(a)=0 then n; fi; end: 0,seq(P(i),i=1..6204);

%Y Cf. A073053, A073054.

%K nonn,base,easy

%O 0,2

%A _Paolo P. Lava_, May 14 2019