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.

A048151 Triangular array T read by rows: T(n,k)=k mod n, for k=1,2,...,n, n=1,2,...

Original entry on oeis.org

0, 1, 0, 1, 2, 0, 1, 2, 3, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 0
Offset: 1

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Examples

			Triangle begins:
  0;
  1, 0;
  1, 2, 0;
  1, 2, 3, 0;
  1, 2, 3, 4, 0;
  ...
		

Crossrefs

As a sequence, essentially same as A002262.

Programs

  • Mathematica
    Flatten[Table[Mod[k,n],{n,15},{k,n}]] (* Harvey P. Dale, Mar 21 2012 *)
  • Python
    from math import isqrt, comb
    def A048151(n): return n-comb((m:=isqrt(k:=n+1<<1))+(k>m*(m+1)),2) # Chai Wah Wu, Apr 09 2025

Formula

G.f.: x^2*y/((1 - x)*(1 - x*y)^2). - Stefano Spezia, Feb 21 2024