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.

A249764 Numbers which divide the concatenation, in ascending order, of their anti-divisors.

Original entry on oeis.org

15, 30, 105, 120, 150, 222, 375, 585, 1500, 1695, 1755, 1800, 2700, 3449, 3750, 3840, 4891, 6720, 7680, 12000, 13583, 14400, 15000, 18750, 19200, 20940, 28134, 30000, 34800, 35625, 46875, 48000, 68400, 72504, 75000, 93750, 120000, 128400
Offset: 1

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Author

Paolo P. Lava, Nov 05 2014

Keywords

Examples

			Anti-divisors of 15 are 2, 6, 10 and their concatenation in ascending order is 2610. Finally, 2610 / 15 = 174.
		

Crossrefs

Programs

  • Maple
    P:=proc(q) local a,k,n; for n from 3 to q do a:=0;
    for k from 2 to n-1 do if abs((n mod k)-k/2)<1 then a:=a*10^(ilog10(k)+1)+k; fi; od;
    if type(a/n,integer) then print(n); fi; od; end: P(10^9);