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.

A051599 Rows of triangle formed using Pascal's rule except begin and end n-th row with (n+1)st prime.

Original entry on oeis.org

2, 3, 3, 5, 6, 5, 7, 11, 11, 7, 11, 18, 22, 18, 11, 13, 29, 40, 40, 29, 13, 17, 42, 69, 80, 69, 42, 17, 19, 59, 111, 149, 149, 111, 59, 19, 23, 78, 170, 260, 298, 260, 170, 78, 23, 29, 101, 248, 430, 558, 558, 430, 248, 101, 29, 31, 130, 349, 678, 988, 1116, 988, 678, 349, 130, 31
Offset: 0

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Examples

			Triangle begins:
2;
3,  3;
5,  6,   5;
7,  11,  11,  7;
11, 18,  22,  18,  11;
13, 29,  40,  40,  29,  13;
17, 42,  69,  80,  69,  42,   17;
19, 59,  111, 149, 149, 111,  59,  19;
23, 78,  170, 260, 298, 260,  170, 78,  23;
29, 101, 248, 430, 558, 558,  430, 248, 101, 29;
31, 130, 349, 678, 988, 1116, 988, 678, 349, 130, 31;
		

Crossrefs

Cf. A001223; A000040 (left and right edges), A053210 (row sums).

Programs

  • Haskell
    a051599 n k = a051599_tabl !! n !! k
    a051599_row n = a051599_tabl !! n
    a051599_tabl = map fst $ iterate f ([2], a001223_list) where
       f (row, (d:ds)) =  (zipWith (+) ([d] ++ row) (row ++ [d]), ds)
    -- Reinhard Zumkeller, Nov 23 2012
  • Mathematica
    t = {}; Do[r = {}; Do[If[k == 0 || k == n, m = Prime[n + 1], m = t[[n, k]] + t[[n, k + 1]]]; r = AppendTo[r, m], {k, 0, n}]; AppendTo[t, r], {n, 0, 10}]; t (* T. D. Noe, Jul 31 2013 *)

Extensions

Corrected by James Sellers, Dec 15 1999