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.

A333867 Table with T(1,1) = 1; for n>1, T(n,k) is the number of k's in rows 1 through n-1.

Original entry on oeis.org

1, 1, 2, 2, 1, 3, 2, 3, 3, 1, 4, 3, 3, 4, 3, 5, 1, 5, 3, 6, 2, 1, 6, 4, 7, 2, 2, 1, 7, 6, 7, 3, 2, 2, 1, 8, 8, 8, 3, 2, 3, 3, 8, 9, 11, 3, 2, 3, 3, 3, 8, 10, 15, 3, 2, 3, 3, 4, 1, 0, 1, 10, 11, 18, 4, 2, 3, 3, 5, 1, 1, 1, 0, 0, 0, 1, 14, 12, 20, 5, 3, 3, 3, 5, 1, 2, 2, 0, 0, 0, 1, 0, 0, 1, 17, 14, 23, 5, 5
Offset: 1

Views

Author

Keywords

Comments

Equivalently, list 1, where, at stage k>1, write i in list 1 and j in list 2, where i is the number of j's in list 1, for j=1,2,...,m, where m=max number in list 1 from stages 1 to k-1; stage 1 is 1 in list 1.
Differs from A030717 in that this sequence includes 0's. - Sean A. Irvine, Apr 08 2020
Nevertheless, this sequence starts each row with the count of 1's, not 0's, whose counts are not recorded in the sequence (cf. A174382, which is also initialized with a 0). - Peter Munn, Oct 11 2022

Examples

			1;
1;
2;
2, 1;
3, 2;
3, 3, 1;
4, 3, 3;
		

Crossrefs

Cf. A126027 (row lengths), A006920, A030717 (zeros suppressed).
Cf. A174382.
Cf. A253170 (row sums).

Programs

  • Haskell
    import Data.List (sort, group)
    a030717 n k = a030717_tabf !! (n-1) !! (k-1)
    a030717_row n = a030717_tabf !! (n-1)
    a030717_tabf = [1] : f [1] where
       f xs = ys : f ((filter (> 0) ys) ++ xs) where
              ys = h (group $ sort xs) [1..] where
                   h [] _ = []
                   h vss'@(vs:vss) (w:ws)
                     | head vs == w = (length vs) : h vss ws
                     | otherwise    = 0 : h vss' ws
    -- Reinhard Zumkeller, Dec 28 2014
  • Mathematica
    t = {{1}}; Do[AppendTo[t, BinCounts[#, {1, Max[#] + 1}] &[Flatten[t]]], {30}];
    Map[Length, t] (* A126027*)
    Map[Total, t]  (* A253170*)
    Flatten[t]     (* A333867 *)  (* Peter J. C. Moses, Apr 09 2020 *)

Extensions

More terms from Franklin T. Adams-Watters, Dec 14 2006

A253170 Row sums of table A333867.

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 10, 13, 17, 22, 28, 35, 42, 50, 60, 72, 85, 101, 119, 139, 162, 187, 215, 246, 279, 315, 353, 394, 437, 482, 529, 579, 632, 688, 748, 810, 875, 944, 1016, 1094, 1177, 1263, 1351, 1443, 1538, 1637, 1742, 1852, 1966, 2083, 2205, 2330, 2460
Offset: 1

Views

Author

Reinhard Zumkeller, Dec 28 2014

Keywords

Crossrefs

Cf. A333867, A126027, A030719 (first differences).

Programs

  • Haskell
    a253170 = sum . a333867_row

A240508 Row lengths of table A174382.

Original entry on oeis.org

1, 1, 2, 2, 4, 5, 7, 9, 13, 17, 20, 23, 29, 38, 52, 73, 106, 157, 239, 369, 579, 916, 1460, 2338, 3757, 6051, 9761, 15762, 25470, 41176, 66587, 107701, 174223, 281856, 456008, 737790, 1193721, 1931431, 3125070, 5056416
Offset: 1

Views

Author

Reinhard Zumkeller, Apr 06 2014

Keywords

Crossrefs

Cf. A126027.

Programs

  • Haskell
    a240508 = length . a174382_row
Showing 1-3 of 3 results.