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.

A308125 Numbers k that are a multiple of the DENEAT operator applied to k (A073053).

Original entry on oeis.org

0, 22, 44, 66, 88, 123, 264, 369, 462, 615, 660, 738, 759, 852, 957, 1120, 1344, 1568, 1884, 2024, 2068, 2200, 2244, 2288, 2420, 2464, 2640, 2684, 2860, 2912, 3350, 3360, 3584, 3752, 4004, 4048, 4224, 4268, 4400, 4444, 4488, 4620, 4664, 4840, 4884, 5024, 6028, 6204
Offset: 0

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Author

Paolo P. Lava, May 14 2019

Keywords

Comments

The DENEAT operator is also known as the Sisyphus function.
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}.

Examples

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

References

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

Crossrefs

Programs

  • Maple
    P:=proc(n) local a,b,c,d,k; a:=convert(n,base,10); b:=0: c:=0:
    for k from 1 to nops(a) do if a[k] mod 2=0 then b:=b+1; else c:=c+1; fi;
    od: d:=b*10^length(c)+c; a:=n/(d*10^length(length(n))+length(n)):
    if frac(a)=0 then n; fi; end: 0,seq(P(i),i=1..6204);