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.

A260348 Numbers n such that n is divisible by (10^k - digitsum(n)), where k equals the number of digits of digitsum(n).

Original entry on oeis.org

5, 8, 9, 18, 21, 24, 26, 27, 36, 44, 45, 50, 54, 60, 62, 63, 72, 80, 81, 86, 90, 108, 116, 117, 126, 132, 134, 135, 140, 144, 152, 153, 162, 170, 171, 180, 200, 204, 206, 207, 210, 216, 224, 225, 230, 234, 240, 242, 243, 252, 260, 261, 264, 270, 306, 312, 314
Offset: 1

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Author

Pieter Post, Jul 23 2015

Keywords

Comments

This sequence is infinite because all numbers with a digitsum equal to 9 are part of this sequence.

Examples

			a(1) = 5, because 5 divided by (10 - 5) equals 1.
a(7) = 26, because digitsum(26) = 8 and 26 divided by (10 - 8) equals 13.
a(20) = 86, the first member of this sequence where digitsum(n) >= 10. Digitsum(86) = 14, so k = 10^2 - 14 = 86, so 86 is a member of this sequence.
		

Crossrefs

Programs

  • Mathematica
    fQ[n_] := Block[{d = Total@ IntegerDigits@ n, k}, k = IntegerLength@ d;
      Divisible[n, 10^k - d]]; Select[Range@ 314, fQ] (* or *)
    Select[Range@ 314, Divisible[#, (10^(Floor[Log[10, Total@ IntegerDigits@ #]] + 1) - Total@ IntegerDigits@ #)] &] (* Michael De Vlieger, Aug 05 2015 *)
  • PARI
    isok(n)=my(sd = sumdigits(n), nsd = #digits(sd)); n % (10^nsd - sd) == 0; \\ Michel Marcus, Aug 05 2015
  • Python
    def sod(n,m):
        kk = 0
        while n > 0:
            kk= kk+(n%m)
            n =int(n//m)
        return kk
    for c in range (1, 10**6):
        k=len(str(sod(c,10)))
        kl=10**k-sod(c,10)
        if c%kl==0:
            print (c)