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 1-4 of 4 results.

A035400 Differences of A035399.

Original entry on oeis.org

1, 1, 2, 1, 2, 1, 4, 1, 1, 5, 1, 1, 3, 6, 1, 1, 2, 1, 10, 1, 1, 2, 1, 3, 14, 1, 1, 2, 1, 2, 1, 5, 17, 1, 1, 2, 1, 2, 1, 5, 1, 8, 20, 1, 1, 2, 1, 2, 1, 4, 1, 1, 6, 3, 33, 1, 1, 2, 1, 2, 1, 4, 1, 1, 6, 1, 3, 8, 1, 44, 1, 1, 2, 1, 2, 1, 4, 1, 1, 5, 1, 1, 3, 7, 2, 1, 14, 53, 1, 1, 2, 1, 2, 1, 4, 1, 1, 5, 1
Offset: 1

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Author

Keywords

Crossrefs

A186130 Positions of the odd partitions of (2k+1) in reverse lexicographic order converge to this limiting sequence.

Original entry on oeis.org

1, 4, 9, 12, 21, 24, 26, 30, 47, 50, 52, 59, 62, 67, 99, 102, 104, 110, 113, 116, 126, 129, 133, 139, 197, 200, 202, 208, 211, 214, 227, 231, 234, 238, 254, 256, 260, 265, 272, 375, 378, 380, 386, 389, 392, 404, 407, 411, 414, 418, 440, 443, 450, 452, 456, 461, 486, 489, 494, 500, 508, 686, 689, 691
Offset: 1

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Author

Wouter Meeussen, Feb 13 2011

Keywords

Examples

			The odd partitions of (2*4+1) occur at positions 1, 4, 9, 12, 19, 21, 25, and 30. For (2*5+1) they occur at 1, 4, 9, 12, 20, ..., so for k=5 only four terms have stabilized, giving a(1) = 1, a(2) = 4, a(3) = 9, and a(4) = 12.
		

Crossrefs

First differences give A186203.

Programs

  • Mathematica
    <?EvenQ],1]],{n,39,39+2,2}];{{diffat}}=Position[Take[Last[it],Length[First[it] ] ] - First[it] , a /;(a!=0),1,1]; Take[First[it],diffat -1 ]

A186131 Positions of the odd partitions of (2k) in reverse lexicographic order converge to this limiting sequence.

Original entry on oeis.org

2, 5, 7, 13, 16, 19, 31, 34, 38, 41, 45, 68, 71, 76, 79, 86, 88, 92, 97, 140, 143, 148, 151, 159, 162, 164, 168, 181, 184, 189, 195, 273, 276, 281, 284, 293, 296, 298, 302, 317, 319, 326, 329, 334, 353, 356, 360, 366, 373, 509, 512, 517, 520, 529, 532, 534, 538, 554, 557, 559, 566, 569, 574, 601
Offset: 1

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Author

Wouter Meeussen, Feb 13 2011

Keywords

Examples

			The odd partitions of (2*4) occur at positions 2, 5, 7, 14, 17 and 22. For (2*5) they occur at 2, 5, 7, 13, ... so for k=5 only the first three terms have stabilized, giving a(1) = 2, a(2) = 5, and a(3) = 7.
		

Crossrefs

First differences give A186204.

Programs

  • Mathematica
    <?EvenQ], 1]], {n, 36, 36+2, 2}]; {{diffat}}=Position[Take[Last[it], Length[First[it] ] ] - First[it] , a /; (a!=0), 1, 1]; Take[First[it], diffat -1 ]

A308916 Irregular triangular array: row n shows positions of strict partitions of n among all partitions of n, using Mathematica ordering.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 1, 2, 3, 1, 2, 3, 6, 1, 2, 3, 5, 6, 1, 2, 3, 5, 6, 9, 1, 2, 3, 5, 6, 8, 9, 14, 1, 2, 3, 5, 6, 8, 9, 14, 15, 23, 1, 2, 3, 5, 6, 8, 9, 13, 14, 15, 21, 24, 1, 2, 3, 5, 6, 8, 9, 13, 14, 15, 21, 22, 25, 33, 34, 1, 2, 3, 5, 6, 8, 9, 13, 14, 15
Offset: 1

Views

Author

Clark Kimberling, Jun 30 2019

Keywords

Examples

			1
1
1   2
1   2
1   2   3
1   2   3   6
1   2   3   5   6
1   2   3   5   6   9
1   2   3   5   6   8   9   14
1   2   3   5   6   8   9   14   15   23
Strict partitions of 6: {6}, {5, 1}, {4, 2}, {3, 2, 1}, which occupy positions 1,2,3,6 in the ordering of all partitions of 6: {6}, {5, 1}, {4, 2}, {4, 1, 1}, {3, 3}, {3, 2, 1}, {3, 1, 1, 1}, {2, 2, 2}, {2, 2, 1, 1}, {2, 1, 1, 1, 1}, {1, 1, 1, 1, 1, 1}
		

Crossrefs

Programs

  • Mathematica
    p[n_] := IntegerPartitions[n];
    d[n_] := Select[p[n], Max[Length /@ Split@#] == 1 &];
    t = Table[Flatten[Table[Position[p[n], d[n][[k]]], {k, 1, Length[d[n]]}]], {n, 1, 15}]
    Flatten[t]  (* A308916, sequence *)
Showing 1-4 of 4 results.