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 1-10 of 14 results. Next

A209972 Number of binary words of length n avoiding the subword given by the binary expansion of k; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 3, 1, 1, 1, 2, 3, 4, 1, 1, 1, 2, 4, 5, 5, 1, 1, 1, 2, 4, 7, 8, 6, 1, 1, 1, 2, 4, 7, 12, 13, 7, 1, 1, 1, 2, 4, 7, 12, 20, 21, 8, 1, 1, 1, 2, 4, 7, 12, 21, 33, 34, 9, 1, 1, 1, 2, 4, 8, 13, 20, 37, 54, 55, 10, 1, 1, 1, 2, 4, 8, 15, 24, 33, 65, 88, 89, 11, 1, 1
Offset: 0

Views

Author

Alois P. Heinz, Mar 16 2012

Keywords

Examples

			Square array begins:
  1,  1,  1,   1,   1,   1,   1,   1,   1, ...
  1,  1,  2,   2,   2,   2,   2,   2,   2, ...
  1,  1,  3,   3,   4,   4,   4,   4,   4, ...
  1,  1,  4,   5,   7,   7,   7,   7,   8, ...
  1,  1,  5,   8,  12,  12,  12,  13,  15, ...
  1,  1,  6,  13,  20,  21,  20,  24,  28, ...
  1,  1,  7,  21,  33,  37,  33,  44,  52, ...
  1,  1,  8,  34,  54,  65,  54,  81,  96, ...
  1,  1,  9,  55,  88, 114,  88, 149, 177, ...
		

Crossrefs

Columns give: 0, 1: A000012, 2: A001477(n+1), 3: A000045(n+2), 4, 6: A000071(n+3), 5: A005251(n+3), 7: A000073(n+3), 8, 12, 14: A008937(n+1), 9, 11, 13: A049864(n+2), 10: A118870, 15: A000078(n+4), 16, 20, 24, 26, 28, 30: A107066, 17, 19, 23, 25, 29: A210003, 18, 22: A209888, 21: A152718(n+3), 27: A210021, 31: A001591(n+5), 32: A001949(n+5), 33, 35, 37, 39, 41, 43, 47, 49, 53, 57, 61: A210031.
Main diagonal equals A234005 or column k=0 of A233940.

Programs

  • Mathematica
    A[n_, k_] := Module[{bb, cnt = 0}, Do[bb = PadLeft[IntegerDigits[j, 2], n]; If[SequencePosition[bb, IntegerDigits[k, 2], 1]=={}, cnt++], {j, 0, 2^n-1 }]; cnt];
    Table[A[n-k, k], {n, 0, 12}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Nov 01 2021 *)

A234005 Number of binary words of length n avoiding the subword given by the binary expansion of n.

Original entry on oeis.org

1, 1, 3, 5, 12, 21, 33, 81, 177, 338, 667, 1178, 2031, 4105, 6872, 20569, 42744, 84457, 167863, 315633, 590081, 1325032, 2366125, 4408350, 8146016, 16474904, 30266484, 67320433, 112454976, 230099960, 417825921, 1333610936, 2714234540, 5411487988, 10800172911
Offset: 0

Views

Author

Alois P. Heinz, Dec 18 2013

Keywords

Examples

			a(0) = 1: the empty word.
a(1) = 1: 0.
a(2) = 3: 00, 01, 11.
a(3) = 5: 000, 001, 010, 100, 101.
a(4) = 12: 0000, 0001, 0010, 0011, 0101, 0110, 0111, 1010, 1011, 1101, 1110, 1111.
		

Crossrefs

Main diagonal of A209972.
Column k=0 of A233940.

A228612 Number of (possibly overlapping) occurrences of the subword given by the binary expansion of n in all binary words of length n.

Original entry on oeis.org

0, 1, 1, 4, 4, 12, 32, 80, 80, 192, 448, 1024, 2304, 5120, 11264, 24576, 24576, 53248, 114688, 245760, 524288, 1114112, 2359296, 4980736, 10485760, 22020096, 46137344, 96468992, 201326592, 419430400, 872415232, 1811939328, 1811939328, 3758096384, 7784628224
Offset: 0

Views

Author

Alois P. Heinz, Dec 18 2013

Keywords

Comments

a(2^n) = a(2^n-1) for n>0.

Examples

			a(3) = 4 because we have one subword 11 in each of 011, 110 and two overlapping occurrences of 11 in 111.
a(4) = 4 because we have one subword 100 in each of 0100, 1000, 1001, 1100 and no other occurrences in binary words of length 4.
a(5) = 12 because we have one subword 101 in each of 00101, 01010, 01011, 01101, 10100, 10110, 10111, 11010, 11011, 11101 and two overlapping occurrences of 101 in 10101.
		

Crossrefs

Cf. A233940.

Formula

a(n) = Sum_{k>0} k*A233940(n,k).

A229293 Number of binary words of length n with exactly k (possibly overlapping) occurrences of the subword given by the binary expansion of n for maximal k with at least one word.

Original entry on oeis.org

1, 1, 1, 1, 4, 1, 1, 1, 1, 18, 1, 6, 1, 1, 40, 1, 8, 1, 4, 33, 1, 1, 17, 42, 1120, 1, 12, 11, 448, 1, 1, 1, 84, 52, 1, 985, 1, 10, 1, 316, 3360, 1, 1, 75, 144, 1, 1, 12, 1, 504, 180, 15, 7920, 102, 1, 16, 220, 14, 11440, 17, 1, 1, 264, 1, 20, 3206, 399, 1, 4
Offset: 0

Views

Author

Alois P. Heinz, Dec 18 2013

Keywords

Examples

			a(4) = 4 because there are 4 binary words of length 4 with one occurrence of 100, namely 0100, 1000, 1001, 1100, and no words with more than one occurrence of 100.
		

Crossrefs

Last (positive) terms of rows of A233940.

A229905 Number of binary words of length n with exactly one occurrence of the subword given by the binary expansion of n.

Original entry on oeis.org

0, 1, 1, 2, 4, 10, 30, 26, 78, 156, 278, 722, 1827, 3140, 7800, 5810, 21016, 40260, 76104, 173836, 394492, 520775, 1376090, 3080882, 6887040, 12734023, 28266044, 44217698, 114969792, 211934801, 464129402, 354151217, 1360414116, 2644465928, 5134476403
Offset: 0

Views

Author

Alois P. Heinz, Dec 19 2013

Keywords

Examples

			a(1) = 1: 1.
a(2) = 1: 10.
a(3) = 2: 011, 110.
a(4) = 4: 0100, 1000, 1001, 1100.
a(5) = 10: 00101, 01010, 01011, 01101, 10100, 10110, 10111, 11010, 11011, 11101.
		

Crossrefs

Column k=1 of A233940.

A236231 Number of binary words of length n with exactly 2 (possibly overlapping) occurrences of the subword given by the binary expansion of n.

Original entry on oeis.org

0, 0, 0, 1, 0, 1, 1, 13, 1, 18, 68, 142, 237, 862, 1672, 3188, 1768, 6078, 16090, 32566, 62214, 181695, 380903, 802572, 1634880, 3784693, 7871112, 17020646, 36800640, 78582498, 168074511, 206295476, 209557176, 490017420, 1097340244, 2222684855, 5116364054
Offset: 0

Views

Author

Alois P. Heinz, Jan 20 2014

Keywords

Crossrefs

Column k=2 of A233940.

A236232 Number of binary words of length n with exactly 3 (possibly overlapping) occurrences of the subword given by the binary expansion of n.

Original entry on oeis.org

5, 0, 0, 10, 6, 1, 84, 40, 1662, 8, 276, 1948, 2220, 1788, 52903, 63836, 92548, 108160, 527238, 691832, 4591942, 4085120, 14751215, 22719212, 116689525, 10635080, 42281072, 136612465, 216703500, 987830670, 1083905462, 3170868937, 5311691060, 8407495040
Offset: 7

Views

Author

Alois P. Heinz, Jan 20 2014

Keywords

Crossrefs

Column k=3 of A233940.

A236233 Number of binary words of length n with exactly 4 (possibly overlapping) occurrences of the subword given by the binary expansion of n.

Original entry on oeis.org

2, 0, 0, 1, 0, 0, 1, 0, 829, 0, 1, 135, 33, 1, 13240, 6875, 4214, 1120, 32898, 13380, 916700, 124480, 1436212, 984719, 64373760, 126300, 1658572, 10718156, 10201655, 151128452, 59698016, 302737587, 335666252, 302196960, 1826553416, 42810588352, 9670953778
Offset: 7

Views

Author

Alois P. Heinz, Jan 20 2014

Keywords

Crossrefs

Column k=4 of A233940.

A236234 Number of binary words of length n with exactly 5 (possibly overlapping) occurrences of the subword given by the binary expansion of n.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 394, 0, 0, 4, 0, 0, 2874, 458, 42, 0, 675, 12, 135358, 448, 65247, 8058, 34741899, 84, 23560, 532949, 199274, 19005607, 1503366, 19302273, 10429164, 3054912, 67835066, 12419002159, 419211720, 185903568, 36708519210, 17236630474
Offset: 7

Views

Author

Alois P. Heinz, Jan 20 2014

Keywords

Crossrefs

Column k=5 of A233940.

A236235 Number of binary words of length n with exactly 6 (possibly overlapping) occurrences of the subword given by the binary expansion of n.

Original entry on oeis.org

181, 0, 0, 0, 0, 0, 535, 17, 0, 0, 1, 0, 14082, 0, 978, 1, 18383716, 0, 52, 15824, 985, 1995824, 12572, 806911, 127964, 3360, 1121590, 3388924416, 8831268, 767760, 5674830623, 1127556150, 436806956, 75269404, 2826220760, 623517360, 178352390026, 4750656064
Offset: 15

Views

Author

Alois P. Heinz, Jan 20 2014

Keywords

Crossrefs

Column k=6 of A233940.
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