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.

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A012772 Take every 5th term of Padovan sequence A000931, beginning with the sixth term.

Original entry on oeis.org

1, 3, 12, 49, 200, 816, 3329, 13581, 55405, 226030, 922111, 3761840, 15346786, 62608681, 255418101, 1042002567, 4250949112, 17342153393, 70748973084, 288627200960, 1177482265857, 4803651498529, 19596955630177
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A012781 (partial sums).

Programs

  • Magma
    I:=[1, 3, 12]; [n le 3 select I[n] else 5*Self(n-1)-4*Self(n-2)+Self(n-3): n in [1..30]]; // Vincenzo Librandi, Apr 18 2012
  • Mathematica
    CoefficientList[Series[(1-x)^2/(1-5*x+4*x^2-x^3),{x,0,33}],x] (* Vincenzo Librandi, Apr 18 2012 *)
    LinearRecurrence[{5,-4,1},{1,3,12},30] (* Harvey P. Dale, Aug 15 2024 *)

Formula

a(n+3) = 5*a(n+2) - 4*a(n+1) + a(n).
G.f.: (1-x)^2/(1-5*x+4*x^2-x^3). - Colin Barker, Feb 02 2012

A012864 Take every 5th term of Padovan sequence A000931, beginning with the first term.

Original entry on oeis.org

1, 1, 3, 12, 49, 200, 816, 3329, 13581, 55405, 226030, 922111, 3761840, 15346786, 62608681, 255418101, 1042002567, 4250949112, 17342153393, 70748973084, 288627200960, 1177482265857, 4803651498529, 19596955630177
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A012855.

Programs

  • Magma
    I:=[1, 1, 3]; [n le 3 select I[n] else 5*Self(n-1)-4*Self(n-2)+Self(n-3): n in [1..30]]; // Vincenzo Librandi, Apr 18 2012
  • Mathematica
    LinearRecurrence[{5,-4, 1},{1,1,3},30] (* Vincenzo Librandi, Apr 18 2012 *)

Formula

a(n+3) = 5*a(n+2) - 4*a(n+1) + a(n).
O.g.f.: (1-4x+2x^2)/(1-5x+4x^2-x^3). a(n+1)=A012772(n). - R. J. Mathar, May 28 2008

A112882 Indices of prime Padovan numbers: values of k such that A000931(k+5) is prime.

Original entry on oeis.org

3, 4, 5, 7, 8, 14, 19, 30, 37, 84, 128, 469, 666, 1262, 1573, 2003, 2210, 2289, 4163, 5553, 6567, 8561, 11230, 18737, 35834, 44259, 536485, 727734
Offset: 1

Views

Author

Eric W. Weisstein, Oct 05 2005

Keywords

Crossrefs

Formula

a(n) = A152870(n) - 5. - Amiram Eldar, Nov 10 2024

Extensions

a(27) from Eric W. Weisstein, May 22 2009
a(28) from Eric W. Weisstein, Apr 10 2011

A153462 Triangle read by rows, = A000931(n-k+3) * (A000073 * 0^(n-k)).

Original entry on oeis.org

1, 0, 1, 1, 0, 1, 1, 1, 0, 2, 1, 1, 1, 0, 4, 2, 1, 1, 2, 0, 7, 2, 2, 1, 2, 4, 0, 13, 3, 2, 2, 2, 4, 7, 0, 24, 4, 3, 2, 4, 4, 7, 13, 0, 44, 5, 4, 3, 4, 8, 7, 13, 24, 0, 81, 7, 5, 4, 6, 8, 14, 13, 24, 44, 0, 149, 9, 7, 5, 8, 12, 14, 26, 24, 44, 81, 0, 274
Offset: 3

Views

Author

Gary W. Adamson, Dec 27 2008

Keywords

Comments

An eigentriangle by rows, the Padovan sequence convolved with the tribonacci numbers.
Sum of n-th row terms = rightmost term of next row. Row sums = the tribonacci numbers, A000073.

Examples

			First few rows of the triangle =
   1;
   0, 1;
   1, 0, 1;
   1, 1, 0,  2;
   1, 1, 1,  0,  4;
   2, 1, 1,  2,  0,  7;
   2, 2, 1,  2,  4,  0, 13;
   3, 2, 2,  2,  4,  7,  0, 24;
   4, 3, 2,  4,  4,  7, 13,  0, 44;
   5, 4, 3,  4,  8,  7, 13, 24,  0, 81;
   7, 5, 4,  6,  8, 14, 13, 24, 44,  0, 149;
   9, 7, 5,  8, 12, 14, 26, 24, 44, 81,   0, 274;
  12, 9, 7, 10, 16, 21, 26, 48, 44, 81, 149,   0, 504;
  ...
Row 9 = (2, 2, 1, 2, 4, 0, 13) = termwise products of (1, 1, 1, 2, 4, 7, 13) and (2, 2, 1, 1, 1, 0, 1). Dot product = 24 = A000073(8).
		

Crossrefs

Formula

Triangle read by rows, = A000931(n-k+3) * (A000073 * 0^(n-k)).
Equals infinite lower triangular matrices P*M; where P = a matrix with the Padovan sequence in every column starting with offset 3: (1, 0, 1, 1, 1, 2, 2, 3, 4, 5, ...).
M = an infinite lower triangular matrix with the tribonacci sequence prefaced with a 1 as the main diagonal: (1, 1, 1, 2, 4, 7, 13, ...) and the rest zeros.

A216714 a(n) = 2^(n-5) - A000931(n).

Original entry on oeis.org

0, 1, 3, 6, 14, 29, 60, 123, 249, 503, 1012, 2032, 4075, 8164, 16347, 32719, 65471, 130986, 262030, 524137, 1048376, 2096887, 4193953, 8388143, 16776600, 33553616, 67107783, 134216296, 268433559, 536868399, 1073738495, 2147479238, 4294961454, 8589926853, 17179858932, 34359724787, 68719458745, 137438929639, 274877875372, 549755772064
Offset: 5

Views

Author

N. J. A. Sloane, Sep 14 2012

Keywords

Comments

It is conjectured that this sequence (with a different offset) and A038360 are the same.

Crossrefs

Programs

  • Magma
    I:=[0, 1, 3, 6]; [n le 4 select I[n] else 2*Self(n-1)+Self(n-2)-Self(n-3)-2*Self(n-4): n in [1..40]]; // Vincenzo Librandi, Mar 11 2013
    
  • Mathematica
    CoefficientList[Series[-x (-1 - x + x^2)/((2 x - 1) (x^3 + x^2 - 1)), {x, 0, 40}], x] (* Vincenzo Librandi, Mar 11 2013 *)
    LinearRecurrence[{2,1,-1,-2},{0,1,3,6},40] (* Harvey P. Dale, Aug 22 2021 *)
  • PARI
    a(n)=([0,1,0,0; 0,0,1,0; 0,0,0,1; -2,-1,1,2]^(n-5)*[0;1;3;6])[1,1] \\ Charles R Greathouse IV, Sep 09 2016

Formula

G.f.: -x^6*(-1-x+x^2) / ( (2*x-1)*(x^3+x^2-1) ). - R. J. Mathar, Sep 16 2012
a(n) = 2*a(n-1)+a(n-2)-a(n-3)-2*a(n-4). - Vincenzo Librandi, Mar 11 2013

A291289 The Padovan sequence A000931 doubled.

Original entry on oeis.org

2, 0, 0, 2, 0, 2, 2, 2, 4, 4, 6, 8, 10, 14, 18, 24, 32, 42, 56, 74, 98, 130, 172, 228, 302, 400, 530, 702, 930, 1232, 1632, 2162, 2864, 3794, 5026, 6658, 8820, 11684, 15478, 20504, 27162, 35982, 47666, 63144, 83648, 110810, 146792, 194458, 257602, 341250
Offset: 0

Views

Author

N. J. A. Sloane, Aug 29 2017

Keywords

Comments

Like A000931, this sequence has the property that the largest of any four consecutive terms equals the sum of the two smallest.

Crossrefs

Cf. A000931.

Programs

  • Mathematica
    CoefficientList[Series[2*(1 - x^2)/(1 - x^2 - x^3), {x, 0, 49}], x] (* Michael De Vlieger, Mar 21 2023 *)

Formula

G.f.: 2*(1-x^2)/(1-x^2-x^3).

A012493 Take every 5th term of Padovan sequence A000931, beginning with the fifth term.

Original entry on oeis.org

0, 2, 9, 37, 151, 616, 2513, 10252, 41824, 170625, 696081, 2839729, 11584946, 47261895, 192809420, 786584466, 3208946545, 13091204281, 53406819691, 217878227876, 888855064897, 3626169232672, 14793304131648, 60350698792449, 246206446668325, 1004422742303477
Offset: 0

Views

Author

Keywords

Programs

  • Magma
    I:=[0, 2, 9]; [n le 3 select I[n] else 5*Self(n-1)-4*Self(n-2)+Self(n-3): n in [1..30]]; // Vincenzo Librandi, Apr 17 2012
  • Mathematica
    CoefficientList[Series[x*(2-x)/(1-5*x+4*x^2-x^3),{x,0,30}],x] (* Vincenzo Librandi, Apr 17 2012 *)
    LinearRecurrence[{5,-4,1},{0,2,9},30] (* Harvey P. Dale, Nov 24 2018 *)

Formula

a(n+3) = 5*a(n+2) - 4*a(n+1) + a(n).
G.f.: x*(2-x)/(1-5*x+4*x^2-x^3). - Colin Barker, Feb 02 2012

Extensions

First term corrected by Colin Barker, Feb 02 2012

A018243 Inverse Euler transform of A000931.

Original entry on oeis.org

0, 0, 1, 0, 1, 0, 1, 1, 1, 1, 2, 2, 3, 3, 4, 5, 7, 8, 11, 13, 17, 21, 28, 34, 45, 56, 73, 92, 120, 151, 197, 250, 324, 414, 537, 687, 892, 1145, 1484, 1911, 2479, 3196, 4148, 5359, 6954, 9000, 11687, 15140, 19672, 25516, 33166, 43065, 56010, 72784, 94716, 123185, 160380, 208740, 271913, 354123, 461529, 601436, 784209, 1022505, 1333856
Offset: 1

Views

Author

Keywords

Examples

			x^3 + x^5 + x^7 + x^8 + x^9 + x^10 + 2*x^11 + 2*x^12 + 3*x^13 + 3*x^14 + ...
		

Crossrefs

Programs

  • Maple
    # The function EulerInvTransform is defined in A358451.
    a := EulerInvTransform(A000931):
    seq(a(n), n = 1..65); # Peter Luschny, Nov 21 2022
  • Mathematica
    a[n_] := (1/n)*Sum[ MoebiusMu[n/d]*Floor[ Re[ N[ RootSum[ -1-#+#^3&, #^d& ]]]] , {d, Divisors[n]}]; a[2]=0; Table[a[n], {n, 1, 65}] (* Jean-François Alcover, Oct 05 2012, after Michael Somos *)
  • Sage
    z = PowerSeriesRing(ZZ, 'z').gen().O(30)
    r = (1 - (z**2 + z**3))/(1 - z**2)
    F = -z*r.derivative()/r
    [sum(moebius(n//d)*F[d] for d in divisors(n))//n for n in range(1, 24)] # F. Chapoton, Apr 25 2020

Formula

a(n) = A113788(n) unless n=2. - Michael Somos, Apr 06 2012
Reciprocal of g.f. of A000931 = (1 - x^2 - x^3) / (1 - x^2) = 1 - x^3 - x^5 - x^7 - x^9 - ... = Product_{k>0} (1 - x^k)^a(n). - Michael Somos, Jul 17 2012
a(n) ~ A060006^n / n. - Vaclav Kotesovec, Oct 09 2019

Extensions

More terms from Joerg Arndt, Jul 18 2012

A132347 Concatenation of first n members of the Padovan sequence A000931.

Original entry on oeis.org

1, 10, 100, 1001, 10010, 100101, 1001011, 10010111, 100101112, 1001011122, 10010111223, 100101112234, 1001011122345, 10010111223457, 100101112234579, 10010111223457912, 1001011122345791216, 100101112234579121621
Offset: 1

Views

Author

Omar E. Pol, Nov 10 2007

Keywords

Crossrefs

Cf. A000931, A007908, A019523, A102397. See A134732 for another version.

Programs

  • Mathematica
    Module[{nn=20,padseq},padseq=LinearRecurrence[{0,1,1},{1,0,0},nn];Table[FromDigits[ Flatten[ IntegerDigits/@Take[padseq,n]]],{n,nn}]] (* Harvey P. Dale, Feb 18 2024 *)

A133039 a(n) = P(n)^3 - P(n)^2 where P(n) = A000931(n).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 18, 48, 100, 294, 648, 1584, 3840, 8820, 21168, 49284, 115248, 270400, 628660, 1468548, 3420150, 7960000, 18539400, 43120350, 100328400, 233365440, 542672640, 1262045880, 2934442944, 6822962664, 15863704528, 36881698048, 85746672900, 199347278724, 463445232298
Offset: 0

Views

Author

Omar E. Pol, Nov 02 2007

Keywords

Examples

			a(10)=18 because Padovan(10)=3 and 3^3=27 and 3^2=9 and 27-9=18.
		

Crossrefs

Cf. A000290, A000578, A045991. Padovan sequence: A000931.

Programs

  • Mathematica
    P[0] := 1; P[1] := 0; P[2] := 0; P[n_] := P[n] = P[n - 2] + P[n - 3]; Table[P[n]^3 - P[n]^2, {n, 0, 50}] (* G. C. Greubel, Oct 02 2017 *)
  • PARI
    x='x+O('x^50); concat([0, 0, 0, 0, 0, 0, 0, 0], Vec(2*x^8*(x^7-x^6+2*x^5+x^2-2*x+2)/((x -1)*(x^3-2*x^2+3*x-1)*(x^3-x^2+2*x-1)*(x^3-x-1)*(x^6+3*x^5+5*x^4 +5*x^3 +5*x^2+3*x+1)))) \\ G. C. Greubel, Oct 02 2017

Formula

a(n) = P(n)^3 - P(n)^2 = A000931(n)^3 - A000931(n)^2.
G.f.: 2*x^8*(x^7-x^6+2*x^5+x^2-2*x+2) / ((x-1) * (x^3-2*x^2+3*x-1) * (x^3-x^2+2*x-1) * (x^3-x-1) * (x^6+3*x^5+5*x^4+5*x^3+5*x^2+3*x+1)). - Colin Barker, Sep 18 2013

Extensions

Incorrect initial zero of the sequence deleted by Colin Barker, Sep 18 2013
Added more terms, Joerg Arndt, Sep 18 2013
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