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 1-3 of 3 results.

A094781 Array T(i,j), i>=1, j >= 1, forming a two-dimensional version of A090822, read by antidiagonals.

Original entry on oeis.org

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

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Author

N. J. A. Sloane, Jun 12 2004

Keywords

Comments

T(1,i) = T(i,1) = A090822(i). For i and j > 1, T(i,j) = max {k1, k2}, where k1 = curling number of (T(i,1), T(i,2)...,T(i,j-1)), k2 = curling number of (T(1,j), T(2,j)...,T(i-1,j)).
The curling number of a finite string S = (s(1),...,s(n)) is the largest integer k such that S can be written as xy^k for strings x and y (where y has positive length).

Examples

			Array begins:
1 1 2 1 1 2 2 2 3 1 1 2 1 1 2 2 2 3 2 1 ... (A090822)
1 1 2 1 1 2 2 2 3 1 1 2 1 1 2 2 2 3 2 1 ... (A090822)
2 2 2 3 2 2 2 3 2 2 2 3 3 2 ... (A091787)
1 1 3 1 1 3 3 2 1 1 2 1 1 2 ... (A094782)
1 1 2 1 1 2 2 2 3 1 2 1 1 2 ... (A094839)
2 2 2 3 2 1 1 2 1 2 3 2 2 3 ...
2 2 2 3 2 1 1 3 1 2 ...
		

Crossrefs

A094839 5th row of array in A094781.

Original entry on oeis.org

1, 1, 2, 1, 1, 2, 2, 2, 3, 1, 2, 1, 1, 2, 1, 2, 2, 2, 3, 1, 1, 2, 1, 2, 2, 2, 3, 2, 1, 1, 2, 1, 1, 2, 2, 2, 3, 1, 1, 2, 4, 1, 1, 2, 2, 4, 1, 2, 2, 2, 3, 1, 1, 2, 1, 1, 2, 2, 2, 3, 2, 1, 1, 2, 1, 1, 2, 2, 2, 3, 1, 1, 2, 1, 2, 2, 2, 3, 1, 1, 2, 2, 2, 3, 1, 2, 1, 4, 1, 1, 2, 4, 1, 1, 2, 2, 4, 1, 2, 1, 1, 2, 1, 2, 2
Offset: 1

Views

Author

N. J. A. Sloane, Jun 12 2004

Keywords

Crossrefs

Extensions

More terms from David Wasserman, Jun 27 2007

A144646 a(n) = Bell(n) - 2^n + n.

Original entry on oeis.org

0, 0, 0, 0, 3, 25, 145, 756, 3892, 20644, 114961, 676533, 4209513, 27636258, 190882952, 1382925792, 10480076627, 82864738749, 682076544033, 5832741680788, 51724157186816, 474869814059620, 4506715734253041, 44152005846695761, 445958869278028097
Offset: 0

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Author

Keywords

Comments

Number of partitions of an n-set having more than one block of size > 1. - Peter Luschny, Apr 10 2011

Examples

			a(5) = 25 = card({25|134, 35|124, 125|34, 345|12, 45|123, 235|14, 15|234, 145|23, 135|24, 245|13, 25|4|13, 35|4|12, 45|3|12, 5|24|13, 5|12|34, 1|35|24, 35|2|14, 25|3|14, 5|14|23, 1|45|23, 15|4|23, 45|2|13, 15|3|24, 15|2|34, 1|25|34}). - _Peter Luschny_, Apr 10 2011
		

Crossrefs

Programs

  • Magma
    [Bell(n) -2^n +n: n in [0..30]]; // G. C. Greubel, Oct 12 2023
    
  • Mathematica
    Table[BellB[n] - 2^n + n, {n, 0, 24}] (* Amiram Eldar, Nov 23 2019 *)
  • SageMath
    [bell_number(n) - 2^n +n for n in range(31)] # G. C. Greubel, Oct 12 2023
Showing 1-3 of 3 results.