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 11 results. Next

A048504 a(n) = T(n,n), array T given by A048494.

Original entry on oeis.org

1, 2, 7, 28, 101, 326, 967, 2696, 7177, 18442, 46091, 112652, 270349, 638990, 1490959, 3440656, 7864337, 17825810, 40108051, 89653268, 199229461, 440401942, 968884247, 2122317848, 4630511641
Offset: 0

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Author

Keywords

Programs

  • Magma
    [n*(n-1)*2^(n-1) + n + 1 : n in [0..30]]; // Vincenzo Librandi, Sep 25 2011
  • Mathematica
    Table[n(n-1)2^(n-1)+n+1,{n,0,30}] (* or *) LinearRecurrence[{8,-25,38,-28,8},{1,2,7,28,101},30] (* Harvey P. Dale, Jul 29 2021 *)

Formula

a(n) = n*(n-1)*2^(n-1) + n + 1. - Ralf Stephan, Jan 15 2004
G.f.: (-1 - 4*x^4 + 16*x^3 - 16*x^2 + 6*x)/((x-1)^2*(2*x-1)^3). - Maksym Voznyy (voznyy(AT)mail.ru), Aug 13 2009

A048483 Array read by antidiagonals: T(k,n) = (k+1)2^n - k.

Original entry on oeis.org

1, 2, 1, 4, 3, 1, 8, 7, 4, 1, 16, 15, 10, 5, 1, 32, 31, 22, 13, 6, 1, 64, 63, 46, 29, 16, 7, 1, 128, 127, 94, 61, 36, 19, 8, 1, 256, 255, 190, 125, 76, 43, 22, 9, 1, 512, 511, 382, 253, 156, 91, 50, 25, 10, 1, 1024, 1023, 766, 509, 316, 187
Offset: 0

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Comments

n-th difference of (T(k,n),T(k,n-1),...,T(k,0)) is k+1, for n=1,2,3,...; k=0,1,2,...

Examples

			1 2 4 8 16 32 ...
1 3 7 15 31 63 ...
1 4 10 22 46 94 ...
1 5 13 29 61 125 ...
1 6 16 36 76 156 ...
		

Crossrefs

Rows are A000079 (k=0), A000225 (k=1), A033484 (k=2), A036563 (k=3), A048487 (k=4), A048488 (k=5), A048489 (k=6), A048490 (k=7), A048491 (k=8).
Main diagonal is A048493. Cf. A048494.

Formula

G.f.: (1-x+kx)/[(1-x)(1-2x)]. E.g.f.: (k+1)*exp(2x) - k*exp(x).
Recurrences: T(k, n) = 2T(k, n-1)+k = T(k-1, n)+2^n-1, T(k, 0) = 1.

Extensions

Edited by Ralf Stephan, Feb 05 2004

A048495 a(n) = (n-1)*2^n + 2.

Original entry on oeis.org

1, 2, 6, 18, 50, 130, 322, 770, 1794, 4098, 9218, 20482, 45058, 98306, 212994, 458754, 983042, 2097154, 4456450, 9437186, 19922946, 41943042, 88080386, 184549378, 385875970, 805306370, 1677721602, 3489660930, 7247757314
Offset: 0

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Comments

Binomial transform of 1 followed by the odd numbers (2n-1+2*0^n, or abs(A060747)). Binomial transform is A084643. - Paul Barry, Jun 09 2003
Total number of bits of all binary numbers less than 2^n (see example).
Total number of zero bits of all binary numbers less than 2^(n+1). - Olivier Gérard, Feb 25 2014.
Number of permutations of length n>0 avoiding the partially ordered pattern (POP) {1>2, 4>3} of length 4. That is, number of length n permutations having no subsequences of length 4 in which the first element is larger than the second element, and the fourth element is larger than the third element. - Sergey Kitaev, Dec 08 2020

Examples

			a(1)=2 : 0 1
a(2)=6 : 0 1 10 11
a(3)=18 : 0 1 10 11 100 101 110 111
a(4)=50 : 0 1 10 11 100 101 110 111 1000 1001 1010 1011 1100 1101 1110 1111
...
		

Crossrefs

a(n) = T(1, n), array T given by A048494.

Programs

Formula

a(n) - 1 = Sum_{i=0..n-1} (n-i) * 2^(n-i-1) = n*2^(n-1) + (n-1)*2^(n-2) + (n-2)*2^(n-3) + ... + 1*(2^0). - Matthew Erbst (matt(AT)erbst.org), Apr 19 2006
a(n) = 2 * A002064(n-1), n >= 1. - Omar E. Pol, Sep 30 2012
a(n) = a(n-1) + (2^n - 2^(n-1)) * n = a(n-1) + n*2^(n-1). - Olivier Gérard, Feb 25 2014
G.f.: -(4*x^2-3*x+1) / ((x-1)*(2*x-1)^2). - Colin Barker, Jun 29 2014
E.g.f.: exp(x)*(2 + exp(x)*(2*x - 1)). - Stefano Spezia, Feb 14 2025

Extensions

Better description from John W. Layman, May 04 1999

A048496 a(n) = 2^(n-1)*(3*n-4) + 3.

Original entry on oeis.org

1, 2, 7, 23, 67, 179, 451, 1091, 2563, 5891, 13315, 29699, 65539, 143363, 311299, 671747, 1441795, 3080195, 6553603, 13893635, 29360131, 61865987, 130023427, 272629763, 570425347, 1191182339, 2483027971, 5167382531
Offset: 0

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Comments

a(n) = T(2, n), array T given by A048494.

Crossrefs

n-th difference of a(n), a(n-1), ..., a(0) is (1, 4, 7, 10, ...).

Programs

Formula

a(n) = A027992(n-1) + 1 = A053565(n) + 3.
From R. J. Mathar, Oct 31 2008: (Start)
a(n) = 5*a(n-1) - 8*a(n-2) + 4*a(n-3).
G.f.: (1 - 3*x + 5*x^2)/((1-x)(1-2*x)^2). (End)

Extensions

Formula from Ralf Stephan, Jan 15 2004

A048497 a(n) = 2^(n-1)*(4*n - 6) + 4.

Original entry on oeis.org

1, 2, 8, 28, 84, 228, 580, 1412, 3332, 7684, 17412, 38916, 86020, 188420, 409604, 884740, 1900548, 4063236, 8650756, 18350084, 38797316, 81788932, 171966468, 360710148, 754974724, 1577058308, 3288334340, 6845104132
Offset: 0

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Comments

Equals binomial transform of A016813 preceded by a "1": (1, 1, 5, 9, 13, 21, ...). [Gary W. Adamson, Jan 13 2009]

Crossrefs

a(n) = T(3, n), array T given by A048494.
Cf. A016813. [Gary W. Adamson, Jan 13 2009]

Programs

  • Magma
    [2^(n-1)*(4*n-6)+4: n in [0..30]]; // Vincenzo Librandi, Sep 23 2011
  • Mathematica
    LinearRecurrence[{5,-8,4},{1,2,8},30] (* Harvey P. Dale, Apr 16 2019 *)

Formula

From Colin Barker, Oct 07 2012: (Start)
a(n) = 5*a(n-1) - 8*a(n-2) + 4*a(n-3).
G.f.: (1 - 3*x + 6*x^2)/((1-x)*(1-2*x)^2). (End)

Extensions

Formula from Ralf Stephan, Jan 15 2004

A048498 2^(n-1)*(5n-8)+5.

Original entry on oeis.org

1, 2, 9, 33, 101, 277, 709, 1733, 4101, 9477, 21509, 48133, 106501, 233477, 507909, 1097733, 2359301, 5046277, 10747909, 22806533, 48234501, 101711877, 213909509, 448790533, 939524101, 1962934277, 4093640709, 8522825733
Offset: 0

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Crossrefs

a(n)=T(4, n), array T given by A048494.

Programs

Formula

a(0)=1, a(1)=2, a(2)=9, a(n)=5*a(n-1)-8*a(n-2)+4*a(n-3). - Harvey P. Dale, Jun 14 2011
G.f.: (-1+3*x-7*x^2)/((-1+x)(-1+2*x)^2). - Harvey P. Dale, Jun 14 2011

Extensions

Formula from Ralf Stephan, Jan 15 2004

A048499 a(n) = 2^(n-1)*(6*n-10)+6.

Original entry on oeis.org

1, 2, 10, 38, 118, 326, 838, 2054, 4870, 11270, 25606, 57350, 126982, 278534, 606214, 1310726, 2818054, 6029318, 12845062, 27262982, 57671686, 121634822, 255852550, 536870918, 1124073478, 2348810246, 4898947078, 10200547334, 21206401030, 44023414790
Offset: 0

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Author

Keywords

Crossrefs

Cf. A048494.

Programs

  • Magma
    [2^(n-1)*(6*n-10)+6: n in [0..30]]; // Vincenzo Librandi, Sep 23 2011
    
  • PARI
    Vec((1-3*x+8*x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ Colin Barker, Aug 24 2016

Formula

a(n) = T(5, n), array T given by A048494.
a(0)=1, a(1)=2, a(2)=10, a(n) = 5*a(n-1)-8*a(n-2)+4*a(n-3). - Harvey P. Dale and Vincenzo Librandi, Sep 23 2011
G.f.: (1-3*x+8*x^2) / ((1-x)*(1-2*x)^2). - Colin Barker, Aug 24 2016

Extensions

Formula from Ralf Stephan, Jan 15 2004

A048500 a(n) = 2^(n-1)*(7*n-12)+7.

Original entry on oeis.org

1, 2, 11, 43, 135, 375, 967, 2375, 5639, 13063, 29703, 66567, 147463, 323591, 704519, 1523719, 3276807, 7012359, 14942215, 31719431, 67108871, 141557767, 297795591, 624951303, 1308622855, 2734686215, 5704253447, 11878268935, 24696061959, 51271172103
Offset: 0

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Author

Keywords

Crossrefs

Cf. A048494.

Programs

  • Magma
    [2^(n-1)*(7*n-12)+7: n in [0..30]]; // Vincenzo Librandi, Sep 23 2011
    
  • PARI
    Vec((1-3*x+9*x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ Colin Barker, Aug 24 2016

Formula

a(n) = T(6, n), array T given by A048494.
a(0)=1, a(1)=2, a(2)=11, a(n) = 5*a(n-1)-8*a(n-2)+4*a(n-3). - Harvey P. Dale and Vincenzo Librandi, Sep 23 2011
G.f.: (1-3*x+9*x^2) / ((1-x)*(1-2*x)^2). - Colin Barker, Aug 24 2016

Extensions

Formula from Ralf Stephan, Jan 15 2004

A048501 a(n) = 2^(n-1)*(8*n-14)+8.

Original entry on oeis.org

1, 2, 12, 48, 152, 424, 1096, 2696, 6408, 14856, 33800, 75784, 167944, 368648, 802824, 1736712, 3735560, 7995400, 17039368, 36175880, 76546056, 161480712, 339738632, 713031688, 1493172232, 3120562184, 6509559816, 13555990536, 28185722888, 58518929416
Offset: 0

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Comments

a(n) = T(7, n), array T given by A048494.

Programs

  • Magma
    [2^(n-1)*(8*n-14)+8 : n in [0..30]]; // Vincenzo Librandi, Sep 25 2011
    
  • Mathematica
    Table[2^(n-1) (8n-14)+8,{n,0,30}] (* or *) LinearRecurrence[{5,-8,4},{1,2,12},30] (* Harvey P. Dale, Nov 22 2014 *)
  • PARI
    Vec((1-3*x+10*x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ Colin Barker, Aug 24 2016

Formula

G.f.: (1-3*x+10*x^2) / ((1-x)*(1-2*x)^2). - Colin Barker, Aug 24 2016

Extensions

Formula from Ralf Stephan, Jan 15 2004

A048502 a(n) = 2^(n-1)*(9*n-16)+9.

Original entry on oeis.org

1, 2, 13, 53, 169, 473, 1225, 3017, 7177, 16649, 37897, 85001, 188425, 413705, 901129, 1949705, 4194313, 8978441, 19136521, 40632329, 85983241, 181403657, 381681673, 801112073, 1677721609, 3506438153, 7314866185, 15233712137, 31675383817, 65766686729
Offset: 0

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Author

Keywords

Crossrefs

Cf. A048494.

Programs

Formula

a(n) = T(8, n), array T given by A048494.
a(n) = 2^(n-1)*(9n-16)+9 = A000079(n-1)*A017185(n-2)+9. - Wesley Ivan Hurt, Dec 04 2013
G.f.: (1-3*x+11*x^2) / ((1-x)*(1-2*x)^2). - Colin Barker, Aug 24 2016

Extensions

Formula and more terms from Ralf Stephan, Jan 15 2004
Showing 1-10 of 11 results. Next