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.

A121669 Numbers with sum of digits = 19, divisible by 19 and containing the string "19".

Original entry on oeis.org

17119, 19171, 19342, 19513, 20197, 21907, 33193, 34219, 41914, 51319, 61921, 101935, 102619, 112195, 119035, 119206, 121942, 125191, 171019, 171190, 190171, 190342, 190513, 191026, 191710, 192052, 192223, 193420, 194104, 195130, 195301, 197011, 201970, 204193
Offset: 1

Views

Author

Hassan Taifour (hytaifour(AT)yahoo.co.uk), Sep 10 2006

Keywords

Comments

Conjecture: There are approximately k(n-1)(n-2)^(n-2) terms of this sequence up to 10^n, where k is about e/(19e-19). - Charles R Greathouse IV, Oct 13 2022

Crossrefs

Intersection of A008601, A166459 and A293879.

Programs

  • Mathematica
    d19Q[n_]:=Module[{idn=IntegerDigits[n]},Total[idn]==19&&MemberQ[ Partition[ idn,2,1],{1,9}]]; Select[19*Range[20000],d19Q] (* Harvey P. Dale, Jun 10 2014 *)
  • Python
    def ok(n): s = str(n); return n%19==0 and '19' in s and sum(map(int, s))==19
    print(list(filter(ok, range(205000)))) # Michael S. Branicky, Aug 06 2021

Extensions

More terms from Zak Seidov, Sep 12 2006