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.

Showing 1-2 of 2 results.

A103452 Inverse of number triangle A103451.

Original entry on oeis.org

1, -1, 1, -1, 0, 1, -1, 0, 0, 1, -1, 0, 0, 0, 1, -1, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 0

Views

Author

Paul Barry, Feb 06 2005

Keywords

Comments

Triangle T(n,k), 0 <= k <= n, read by rows given by [ -1, 2, 0, 0, 0, 0, 0, ...] DELTA [1, 0, -1/2, 1/2, 0, 0, 0, 0, 0, ...] where DELTA is the operator defined in A084938. - Philippe Deléham, May 01 2007

Examples

			Triangle begins
   1;
  -1, 1;
  -1, 0, 1;
  -1, 0, 0, 1;
  -1, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 0, 0, 0, 0, 1;
  -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
Production matrix begins
  -1, 1;
  -2, 1, 1;
  -2, 1, 0, 1;
  -2, 1, 0, 0, 1;
  -2, 1, 0, 0, 0, 1;
  -2, 1, 0, 0, 0, 0, 1;
  -2, 1, 0, 0, 0, 0, 0, 1;
  -2, 1, 0, 0, 0, 0, 0, 0, 1;
		

Crossrefs

Cf. A000007 (row sums), A103453, A103454, A103455.

Programs

Formula

T(n,k) = 1 if k = n, -1 if k = 0, otherwise 0.
Sum_{k=0..n} T(n, k) = 0^n (row sums).
Sum_{k=0..floor(n/2)} T(n-k, k) = 0^n - (1-(-1)^n)/2 (diagonal sums).
G.f.: (1 - 2*x + y*x^2)/((1-x)*(1-y*x)). - Philippe Deléham, Feb 11 2012

A114808 The numbers 5^n-1 written in groups of three digits, with leading zeros omitted.

Original entry on oeis.org

424, 124, 624, 312, 415, 624, 781, 243, 906, 241, 953, 124, 976, 562, 448, 828, 124, 244, 140, 624, 122, 70, 312, 461, 35, 156, 243, 51, 757, 812, 415, 258, 789, 62, 476, 293, 945, 312, 438, 146, 972, 656, 241, 907, 348, 632, 812, 495, 367, 431, 640, 624, 476, 837, 158, 203, 124, 238, 418, 579
Offset: 1

Views

Author

Jonathan Vos Post, Feb 19 2006

Keywords

Examples

			4, 24, 124, 624, 3124, 15624, ...
		

Crossrefs

Programs

  • Maple
    L := [] ;
    for n from 1 to 30 do
        dggs := ListTools[Reverse](convert(5^n-1,base,10) );
        L := [op(L),op(dggs)] ;
    end do:
    for k from 1 to nops(L)-3 by 3 do
        op(k,L)*100+op(k+1,L)*10+op(k+2,L) ;
        printf("%d,",%) ;
    end do: # R. J. Mathar, Jun 23 2014
  • Mathematica
    FromDigits[#] & /@ Partition[ Flatten@ IntegerDigits@ Table[5^n - 1, {n, 22}], 3] (* Robert G. Wilson v, Jun 23 2014 *)

Extensions

Definition and terms realigned with A114645 by Robert G. Wilson v, Jun 23 2014
Showing 1-2 of 2 results.