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.

A258197 Arithmetic derivative of Pascal's triangle.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 4, 5, 4, 0, 0, 1, 7, 7, 1, 0, 0, 5, 8, 24, 8, 5, 0, 0, 1, 10, 12, 12, 10, 1, 0, 0, 12, 32, 92, 59, 92, 32, 12, 0, 0, 6, 60, 124, 165, 165, 124, 60, 6, 0, 0, 7, 39, 244, 247, 456, 247, 244, 39, 7, 0, 0, 1, 16, 103, 371, 493, 493, 371, 103, 16, 1, 0
Offset: 0

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Author

Reinhard Zumkeller, May 26 2015

Keywords

Comments

A258318(n) = number of distinct terms up to row n.

Examples

			.  First 10 rows:                     |  Pascal's triangle:
.  0:  0                              |  1
.  1:  0,0                            |  1,1
.  2:  0,1,0                          |  1,2,1
.  3:  0,1,1,0                        |  1,3,3,1
.  4:  0,4,5,4,0                      |  1,4,6,4,1
.  5:  0,1,7,7,1,0                    |  1,5,10,10,5,1
.  6:  0,5,8,24,8,5,0                 |  1,6,15,20,15,6,1
.  7:  0,1,10,12,12,10,1,0            |  1,7,21,35,35,21,7,1
.  8:  0,12,32,92,59,92,32,12,0       |  1,8,28,56,70,56,28,8,1
.  9:  0,6,60,124,165,165,124,60,6,0  |  1,9,36,84,126,126,84,36,9,1 .
		

Crossrefs

Cf. A003415, A007318, A258290 (central terms), A258317 (row sums), A068312, A258318.

Programs

  • Haskell
    a258197 n k = a258197_tabl !! n !! k
    a258197_row n = a258197_tabl !! n
    a258197_tabl = map (map a003415) a007318_tabl
  • Mathematica
    ad[n_] := n * Plus @@ ((Last[#]/First[#]) & /@ FactorInteger[n]); ad[0] = ad[1] = 0; Table[ad[Binomial[n, k]], {n, 0, 11}, {k, 0, n}] // Flatten (* Amiram Eldar, Apr 13 2025 *)

Formula

T(n,k) = A003415(A007318(n,k)), 0 <= k <= n.
For n > 0: T(n,1) = A003415(n).
For n > 1: T(n,2) = A068312(n-1).