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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A093846 Triangle read by rows: T(n, k) = 10^(n-1) - 1 + k*floor(9*10^(n-1)/n), for 1 <= k <= n.

Original entry on oeis.org

9, 54, 99, 399, 699, 999, 3249, 5499, 7749, 9999, 27999, 45999, 63999, 81999, 99999, 249999, 399999, 549999, 699999, 849999, 999999, 2285713, 3571427, 4857141, 6142855, 7428569, 8714283, 9999997, 21249999, 32499999, 43749999, 54999999, 66249999, 77499999, 88749999, 99999999
Offset: 1

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Author

Amarnath Murthy, Apr 18 2004

Keywords

Comments

10^(n-1)-1 and the n-th row are n+1 numbers in arithmetic progression and the common difference is the largest such that a(n, n) has n digits. This common difference equals A061772(n).

Examples

			Triangle begins:
     9;
    54,   99;
   399,  699,  999;
  3249, 5499, 7749, 9999;
  ...
		

Crossrefs

Programs

  • Magma
    [[10^(n-1) -1 +k*Floor(9*10^(n-1)/n): k in [1..n]]: n in [1..8]]; // G. C. Greubel, Mar 22 2019
    
  • Maple
    A093846 := proc(n,k) RETURN (10^(n-1)-1+k*floor(9*(10^(n-1)/n))); end; for n from 1 to 10 do for k from 1 to n do printf("%d,",A093846(n,k)); od; od; # R. J. Mathar, Jun 23 2006
  • Mathematica
    Table[# -1 +k Floor[9 #/n] &[10^(n-1)], {n, 8}, {k, n}]//Flatten (* Michael De Vlieger, Jul 18 2016 *)
  • PARI
    {T(n,k) = 10^(n-1) -1 +k*floor(9*10^(n-1)/n)}; \\ G. C. Greubel, Mar 22 2019
    
  • Sage
    [[10^(n-1) -1 +k*floor(9*10^(n-1)/n) for k in (1..n)] for n in (1..8)] # G. C. Greubel, Mar 22 2019

Extensions

Corrected and extended by R. J. Mathar, Jun 23 2006
Edited by David Wasserman, Mar 26 2007
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