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 13 results. Next

A239333 Number of n X 1 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of elements above it, modulo 4.

Original entry on oeis.org

2, 5, 12, 28, 66, 156, 368, 868, 2048, 4832, 11400, 26896, 63456, 149712, 353216, 833344, 1966112, 4638656, 10944000, 25820224, 60917760, 143723520, 339087488, 800010496, 1887468032, 4453111040, 10506243072, 24787422208, 58481066496
Offset: 1

Views

Author

R. H. Hardin, Mar 16 2014

Keywords

Comments

Column 1 of A239340.

Examples

			Some solutions for n=5:
..0....2....2....2....0....0....0....0....2....2....2....2....2....0....2....2
..2....0....2....0....2....0....2....0....0....0....0....2....2....2....0....3
..2....2....2....3....2....2....3....0....2....2....3....0....0....0....3....2
..0....0....0....2....2....2....2....0....2....2....3....0....2....0....2....3
..2....2....2....0....2....0....0....0....3....0....2....2....3....2....3....2
		

Formula

Empirical: a(n) = 2*a(n-1) +2*a(n-3).
Empirical g.f.: (2 + x + 2*x^2) / (1 - 2*x - 2*x^3). - Colin Barker, Feb 18 2018

A255115 Number of n-length words on {0,1,2} in which 0 appears only in runs of length 2.

Original entry on oeis.org

1, 2, 5, 12, 28, 66, 156, 368, 868, 2048, 4832, 11400, 26896, 63456, 149712, 353216, 833344, 1966112, 4638656, 10944000, 25820224, 60917760, 143723520, 339087488, 800010496, 1887468032, 4453111040, 10506243072, 24787422208, 58481066496, 137974619136
Offset: 0

Views

Author

Milan Janjic, Feb 14 2015

Keywords

Comments

Apparently a(n) = A239333(n).

Crossrefs

Programs

  • Mathematica
    RecurrenceTable[{a[0] == 1, a[1] == 2,  a[2]== 5, a[n] == 2 a[n - 1] + 2 a[n - 3]}, a[n], {n, 0, 29}]
  • PARI
    Vec(-(x^2+1)/(2*x^3+2*x-1) + O(x^100)) \\ Colin Barker, Feb 15 2015

Formula

a(n+3) = 2*a(n+2) + 2*a(n) with n>1, a(0) = 1, a(1) = 2, a(2)=5.
G.f.: -(x^2+1) / (2*x^3+2*x-1). - Colin Barker, Feb 15 2015
a(n) = A052912(n)+A052912(n-2). - R. J. Mathar, Jun 18 2015

A255116 Number of n-length words on {0,1,2,3} in which 0 appears only in runs of length 2.

Original entry on oeis.org

1, 3, 10, 33, 108, 354, 1161, 3807, 12483, 40932, 134217, 440100, 1443096, 4731939, 15516117, 50877639, 166828734, 547034553, 1793736576, 5881695930, 19286191449, 63239784075, 207364440015, 679951894392, 2229575035401, 7310818426248, 23972310961920
Offset: 0

Views

Author

Milan Janjic, Feb 14 2015

Keywords

Crossrefs

Programs

  • Mathematica
    RecurrenceTable[{a[0] == 1, a[1] == 3,  a[2]== 10, a[n] == 3 a[n - 1] + 3 a[n - 3]}, a[n], {n, 0, 25}]
    LinearRecurrence[{3,0,3},{1,3,10},30] (* Harvey P. Dale, Feb 20 2023 *)
  • PARI
    Vec(-(x^2+1)/(3*x^3+3*x-1) + O(x^100)) \\ Colin Barker, Feb 15 2015

Formula

a(n+3) = 3*a(n+2) + 3*a(n) with n>1, a(0) = 1, a(1) = 3, a(2) = 10.
G.f.: -(x^2+1) / (3*x^3+3*x-1). - Colin Barker, Feb 15 2015
a(n) = A089978(n) + A089978(n-2). - R. J. Mathar, Aug 04 2019

A255117 Number of n-length words on {0,1,2,3,4} in which 0 appears only in runs of length 2.

Original entry on oeis.org

1, 4, 17, 72, 304, 1284, 5424, 22912, 96784, 408832, 1726976, 7295040, 30815488, 130169856, 549859584, 2322700288, 9811480576, 41445360640, 175072243712, 739534897152, 3123921031168, 13195973099520, 55742031986688, 235463812071424, 994639140683776
Offset: 0

Views

Author

Milan Janjic, Feb 14 2015

Keywords

Crossrefs

Programs

  • Mathematica
    RecurrenceTable[{a[0] == 1, a[1] == 4,  a[2]== 17, a[n] == 4 a[n - 1] + 4 a[n - 3]}, a[n], {n, 0, 25}]
  • PARI
    Vec(-(x^2+1)/(4*x^3+4*x-1) + O(x^100)) \\ Colin Barker, Feb 15 2015

Formula

a(n+3) = 4*a(n+2) + 4*a(n) with n>1, a(0) = 1, a(1) = 4, a(2) = 17.
G.f.: -(x^2+1) / (4*x^3+4*x-1). - Colin Barker, Feb 15 2015
a(n) = A089979(n) + A089979(n-2). - R. J. Mathar, Aug 04 2019

A255118 Number of n-length words on {0,1,2,3,4,5} in which 0 appears only in runs of length 2.

Original entry on oeis.org

1, 5, 26, 135, 700, 3630, 18825, 97625, 506275, 2625500, 13615625, 70609500, 366175000, 1898953125, 9847813125, 51069940625, 264844468750, 1373461409375, 7122656750000, 36937506093750, 191554837515625, 993387471328125, 5151624887109375, 26715898623125000
Offset: 0

Views

Author

Milan Janjic, Feb 14 2015

Keywords

Crossrefs

Programs

  • Mathematica
    RecurrenceTable[{a[0] == 1, a[1] == 5,  a[2]== 26, a[n] == 5 a[n - 1] + 5 a[n - 3]}, a[n], {n, 0, 20}]
  • PARI
    Vec(-(x^2+1)/(5*x^3+5*x-1) + O(x^100)) \\ Colin Barker, Feb 15 2015

Formula

a(n+3) = 5*a(n+2) + 5*a(n) with n>1, a(0) = 1, a(1) = 5, a(2) = 26.
G.f.: -(x^2+1) / (5*x^3+5*x-1). - Colin Barker, Feb 15 2015

A239334 Number of nX2 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of elements above it, modulo 4.

Original entry on oeis.org

5, 31, 172, 926, 5078, 27861, 152260, 832207, 4550810, 24881731, 136029644, 743697760, 4065948624, 22229220072, 121530709245, 664428372582, 3632538661095, 19859679158791, 108576093277449, 593603153333233
Offset: 1

Views

Author

R. H. Hardin, Mar 16 2014

Keywords

Comments

Column 2 of A239340

Examples

			Some solutions for n=5
..2..0....2..0....2..0....2..1....2..2....0..2....0..2....2..1....2..2....2..1
..3..2....2..1....3..1....2..1....0..3....0..2....0..0....2..2....0..2....2..2
..3..3....0..2....3..2....0..2....3..1....2..0....0..2....2..0....2..1....2..1
..2..2....0..3....2..0....0..0....3..3....0..2....2..0....3..1....0..3....3..1
..3..1....0..0....0..3....0..0....2..1....0..0....3..1....2..0....0..0....3..1
		

Formula

Empirical: a(n) = 9*a(n-1) -28*a(n-2) +74*a(n-3) -181*a(n-4) +236*a(n-5) -261*a(n-6) +234*a(n-7) +200*a(n-8) -279*a(n-9) +104*a(n-10) -268*a(n-11) -36*a(n-12) +156*a(n-13) +104*a(n-14) -32*a(n-15) -16*a(n-16)

A239335 Number of nX3 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of elements above it, modulo 4.

Original entry on oeis.org

12, 172, 2187, 27341, 346028, 4360887, 54774178, 688266175, 8649330696, 108663198449, 1365050486095, 17148274201252, 215420739233431, 2706135761424448, 33994663679676011, 427043158643798758
Offset: 1

Views

Author

R. H. Hardin, Mar 16 2014

Keywords

Comments

Column 3 of A239340

Examples

			Some solutions for n=4
..0..0..0....2..0..0....0..0..2....2..0..0....0..2..2....0..0..2....0..0..2
..0..2..0....0..2..0....2..2..0....0..0..0....0..0..3....2..2..2....2..2..0
..0..2..2....2..2..0....0..0..0....0..0..2....0..0..3....0..3..1....3..2..3
..2..2..3....2..0..0....2..0..2....0..0..3....0..2..0....0..2..2....3..1..2
		

Formula

Empirical recurrence of order 64 (see link above)

A239336 Number of nX4 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of elements above it, modulo 4.

Original entry on oeis.org

28, 926, 27341, 790681, 22952323, 663249556, 19117551262, 550960518608, 15873533676775, 457181997376959, 13166310184133045, 379162593435951456, 10918763117793096685, 314422821700641922733, 9054241291311457562833
Offset: 1

Views

Author

R. H. Hardin, Mar 16 2014

Keywords

Comments

Column 4 of A239340

Examples

			Some solutions for n=3
..2..1..1..0....2..0..0..1....0..0..0..0....2..2..0..0....2..2..2..1
..0..3..2..0....0..2..1..3....2..1..1..2....0..2..1..1....0..3..3..2
..2..0..0..2....3..2..1..2....3..2..1..0....0..0..2..2....0..2..2..0
		

A239337 Number of nX5 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of elements above it, modulo 4.

Original entry on oeis.org

66, 5078, 346028, 22952323, 1527488498, 101276030555, 6693244281896, 442014330398515, 29178369838713161, 1925440562309496640, 127035121924736497404, 8380770923086769177166, 552870412078787577689020
Offset: 1

Views

Author

R. H. Hardin, Mar 16 2014

Keywords

Comments

Column 5 of A239340

Examples

			Some solutions for n=2
..0..2..0..0..1....2..0..1..1..2....2..0..2..2..1....0..2..1..1..0
..2..0..0..2..3....2..0..1..1..3....0..2..2..0..2....2..0..2..3..1
		

A239338 Number of nX6 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of elements above it, modulo 4.

Original entry on oeis.org

156, 27861, 4360887, 663249556, 101276030555, 15397080750829, 2331550702010844, 352742924096563362, 53342694175522093768, 8062792674253914737279, 1218391421349788433734529
Offset: 1

Views

Author

R. H. Hardin, Mar 16 2014

Keywords

Comments

Column 6 of A239340

Examples

			Some solutions for n=2
..2..0..0..1..2..1....0..2..0..2..0..0....2..0..0..1..2..0....2..1..2..1..2..0
..2..0..1..1..3..3....0..3..2..0..1..1....3..2..0..3..2..1....0..3..2..3..0..2
		
Showing 1-10 of 13 results. Next