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.

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A096930 Numbers n for which there are exactly nine k such that n = k + (product of nonzero digits of k).

Original entry on oeis.org

11014, 100774, 111014, 412055, 510142, 511146, 633296, 931395, 983025, 1008305, 1011125, 1031414, 1100774, 1101642, 1108305, 1111014, 1412055, 1510142, 1511146, 1633296, 1931395, 1983025, 2011125, 2011305, 2012725, 2110145
Offset: 1

Views

Author

Klaus Brockhaus, Jul 15 2004

Keywords

Examples

			88486, 96454, 99073, 99154, 99316, 100594, 100654, 100718 and 100732 are the only nine k such that k + (product of nonzero digits of k) = 100774, hence 100774 is a term.
		

Crossrefs

Programs

  • Mathematica
    Select[Tally[Table[n+Times@@DeleteCases[IntegerDigits[n],0],{n, 2111000}]],#[[2]]==9&][[All,1]]//Sort (* Harvey P. Dale, Sep 15 2019 *)
  • PARI
    {c=9;z=2120000;v=vector(z);for(n=1,z+1,k=addpnd(n);if(k<=z,v[k]=v[k]+1));for(j=1,length(v),if(v[j]==c,print1(j,",")))} \\for function addpnd see A096922

A096972 Number of preimages of n (or immediate predecessors) under map f(k) = k + (product of nonzero digits of k).

Original entry on oeis.org

0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 2, 0, 2, 0, 2, 0, 2, 0, 1, 0, 2, 1, 1, 0, 2, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 2, 0, 0, 1, 1, 0, 2, 1, 1, 1, 0, 0, 2, 0, 0, 0, 1, 2, 1, 0, 1, 0, 1, 0, 2, 0, 0, 1, 2, 1, 1, 0, 1, 0, 0, 0, 2, 1, 0, 1, 1, 0, 2, 1, 0, 0, 0, 1, 2, 0, 2, 1, 0, 0, 1, 0, 1, 1, 0, 0, 2, 1, 1, 1, 3, 0, 2, 0
Offset: 1

Views

Author

Robert G. Wilson v, Jul 16 2004

Keywords

Crossrefs

Programs

  • Mathematica
    f[n_] := Block[{s = Sort[ IntegerDigits[ n]]}, While[ s[[1]] == 0, s = Drop[s, 1]]; n + Times @@ s]; t = Table[0, {111}]; Do[ t[[f [n]]]++, {n, 111}]; Table[ t[[n]], {n, 105}]

A095992 a(1) = 30; for n > 1, a(n+1) = a(n) + {product of nonzero digits of a(n)}.

Original entry on oeis.org

30, 33, 42, 50, 55, 80, 88, 152, 162, 174, 202, 206, 218, 234, 258, 338, 410, 414, 430, 442, 474, 586, 826, 922, 958, 1318, 1342, 1366, 1474, 1586, 1826, 1922, 1958, 2318, 2366, 2582, 2742, 2854, 3174, 3258, 3498, 4362, 4506, 4626, 4914, 5058, 5258, 5658
Offset: 1

Views

Author

Julien Piquet (julipiquet(AT)yahoo.fr), Jul 18 2004

Keywords

References

  • From a puzzle; explanation found by Pierre Roger.

Crossrefs

Programs

  • Mathematica
    a[1] = 30; a[n_] := a[n] = Block[{s = Sort[ IntegerDigits[a[n - 1]]]}, While[ s[[1]] == 0, s = Drop[s, 1]]; a[n - 1] + Times @@ s]; Table[ a[n], {n, 50}]
    nxt[n_] := n+Times@@Select[IntegerDigits[n], #>0&]; NestList[nxt,30,50] (* Harvey P. Dale, Jan 08 2011 *)

Extensions

The proposer suggests that this web site may contain other sequences also.
Edited and extended by Robert G. Wilson v and Klaus Brockhaus, Jul 20 2004
Previous Showing 11-13 of 13 results.