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 15 results. Next

A026655 T(n,0) + T(n,1) + ... + T(n,n), T given by A026648.

Original entry on oeis.org

1, 2, 5, 10, 22, 44, 98, 196, 436, 872, 1940, 3880, 8632, 17264, 38408, 76816, 170896, 341792, 760400, 1520800, 3383392, 6766784, 15054368, 30108736, 66984256, 133968512, 298045760, 596091520, 1326151552, 2652303104
Offset: 0

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Author

Keywords

Crossrefs

Cf. A026648.

Programs

  • Mathematica
    CoefficientList[Series[((1+2x)(1+x^2))/(1-4x^2-2x^4),{x,0,45}], x]  (* Harvey P. Dale, Mar 15 2011 *)

Formula

G.f.: ((1+2x)*(1+x^2))/(1-4x^2-2x^4). - Ralf Stephan, Apr 30 2004

A026657 a(n) = Sum_{i=0..n, j=0..n} A026648(i,j).

Original entry on oeis.org

1, 3, 8, 18, 40, 84, 182, 378, 814, 1686, 3626, 7506, 16138, 33402, 71810, 148626, 319522, 661314, 1421714, 2942514, 6325906, 13092690, 28147058, 58255794, 125240050, 259208562, 557254322, 1153345842, 2479497394
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A026648.

Programs

  • Mathematica
    LinearRecurrence[{1, 4, -4, 2, -2}, {1, 3, 8, 18, 40}, 50] (* Paolo Xausa, Feb 02 2024 *)

Formula

G.f.: [(1+2x)(1+x^2)]/[(1-x)(1-4x^2-2x^4)]. - Ralf Stephan, Apr 30 2004

A026649 a(n) = T(2n,n), T given by A026648.

Original entry on oeis.org

1, 3, 8, 36, 114, 558, 1856, 9384, 31942, 164322, 566928, 2948184, 10262004, 53761068, 188306112, 991821456, 3490234182, 18458523378, 65190481904, 345875613144, 1225052975644, 6516499594212, 23134851823872, 123325174525104
Offset: 0

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Author

Keywords

A026650 a(n) = T(2n,n-1), T given by A026648.

Original entry on oeis.org

1, 6, 21, 108, 370, 1908, 6587, 34248, 119142, 623700, 2182818, 11487528, 40391988, 213451560, 753295635, 3993910416, 14136717574, 75152083716, 266650874678, 1420670333640, 5050926317724, 26960309526744, 96015725922014
Offset: 1

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Author

Keywords

A026651 a(n) = T(2n,n-2), T given by A026648.

Original entry on oeis.org

1, 9, 40, 240, 915, 5103, 18704, 101952, 368490, 1990890, 7154928, 38514528, 138086403, 742202055, 2658662560, 14283407616, 51156225342, 274842096462, 984532674800, 5291030979360, 18960255044654, 101937273452454, 365451691152864
Offset: 2

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Author

Keywords

A026652 a(n) = T(2n-1,n-1), T given by A026648.

Original entry on oeis.org

1, 4, 14, 57, 222, 928, 3764, 15971, 66190, 283464, 1190628, 5131002, 21749532, 94153056, 401757672, 1745117091, 7484144598, 32595240952, 140342565620, 612526487822, 2645723309284, 11567425911936, 50095161350616, 219340900447118
Offset: 1

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Author

Keywords

A026653 a(n) = T(2n-1,n-2), T given by A026648.

Original entry on oeis.org

1, 7, 30, 148, 610, 2823, 11690, 52952, 221094, 992190, 4173708, 18642456, 78906516, 351537963, 1495497690, 6652572976, 28420125190, 126308309058, 541492971140, 2405203008440, 10341957297084, 45920564571398, 197952999374468
Offset: 2

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Author

Keywords

A026654 a(n) = T(n,[ n/2 ]), T given by A026648.

Original entry on oeis.org

1, 1, 3, 4, 8, 14, 36, 57, 114, 222, 558, 928, 1856, 3764, 9384, 15971, 31942, 66190, 164322, 283464, 566928, 1190628, 2948184, 5131002, 10262004, 21749532, 53761068, 94153056, 188306112, 401757672, 991821456, 1745117091
Offset: 0

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Author

Keywords

A026656 a(n) = T(n,0) + T(n,1) + ... + T(n,[ n/2 ]), T given by A026648.

Original entry on oeis.org

1, 1, 4, 5, 15, 22, 67, 98, 275, 436, 1249, 1940, 5244, 8632, 23896, 38408, 101419, 170896, 462361, 760400, 1975160, 3383392, 9001276, 15054368, 38623130, 66984256, 175903414, 298045760, 757228832, 1326151552, 3446259592
Offset: 0

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Author

Keywords

A026658 Sum{T(n-k,k)}, 0<=k<=[ n/2 ], T given by A026648.

Original entry on oeis.org

1, 1, 2, 4, 6, 11, 17, 30, 47, 86, 133, 242, 375, 679, 1054, 1914, 2968, 5389, 8357, 15166, 23523, 42698, 66221, 120204, 186425, 338381, 524806, 952592, 1477398, 2681683, 4159081, 7549278, 11708359, 21252226, 32960585, 59827870
Offset: 0

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Author

Keywords

Formula

G.f.: (-x^6+2x^5+x^4+2x^3+x+1)/(x^8-4x^6-x^4-2x^2+1).
Showing 1-10 of 15 results. Next