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 12 results. Next

A083066 5th row of number array A083064.

Original entry on oeis.org

1, 5, 29, 173, 1037, 6221, 37325, 223949, 1343693, 8062157, 48372941, 290237645, 1741425869, 10448555213, 62691331277, 376147987661, 2256887925965, 13541327555789, 81247965334733, 487487792008397, 2924926752050381
Offset: 0

Views

Author

Paul Barry, Apr 21 2003

Keywords

Comments

Let A be the Hessenberg matrix of order n, defined by: A[1,j]=1, A[i,i]:=8, (i>1), A[i,i-1]=-1, and A[i,j]=0 otherwise. Then, for n>=1, a(n-1)=(-1)^(n-1)*charpoly(A,2). - Milan Janjic, Feb 21 2010
An Engel expansion of 3/2 to the base b := 6/5 as defined in A181565, with the associated series expansion 3/2 = b + b^2/5 + b^3/(5*29) + b^4/(5*29*173) + .... Cf. A007051. - Peter Bala, Oct 29 2013

Crossrefs

Programs

Formula

a(n) = (4*6^n+1)/5.
G.f.: (1-2*x)/((1-6*x)*(1-x)).
E.g.f.: (4*exp(6*x)+exp(x))/5.
a(n) = 6*a(n-1)-1 with n>0, a(0)=1. - Vincenzo Librandi, Aug 08 2010
a(n) = 7*a(n-1)-6*a(n-2). - Vincenzo Librandi, Nov 04 2011
a(n) = 6^n - Sum_{i=0..n-1} 6^i for n>0. - Bruno Berselli, Jun 20 2013

A083065 4th row of number array A083064.

Original entry on oeis.org

1, 4, 19, 94, 469, 2344, 11719, 58594, 292969, 1464844, 7324219, 36621094, 183105469, 915527344, 4577636719, 22888183594, 114440917969, 572204589844, 2861022949219, 14305114746094, 71525573730469, 357627868652344
Offset: 0

Views

Author

Paul Barry, Apr 21 2003

Keywords

Comments

Inverse binomial transform of A090040. [Paul Curtz, Jan 11 2009]
Let A be the Hessenberg matrix of order n, defined by: A[1,j]=1, A[i,i]:=7, (i>1), A[i,i-1]=-1, and A[i,j]=0 otherwise. Then, for n>=1, a(n-1)=(-1)^(n-1)*charpoly(A,2). [Milan Janjic, Feb 21 2010]
For an integer x, consider the sequence P(x) of polynomials p_{1}, p_{2}, p_{3}, . . . defined by p_{1} = x-1, p_{n+1} = x*p_{1} - 1. P(5) = This sequence. P(1), P(2), P(3), P(4) are A000004, A123412, A007051, A007583 resp. [K.V.Iyer, Jun 22 2010]
It appears that if s(n) is a first order rational sequence of the form s(0)=2, s(n)= (3*s(n-1)+2)/(2*s(n-1)+3), n>0, then s(n)=2*a(n)/(2*a(n)-1), n>0.
An Engel expansion of 5/3 to the base b := 5/4 as defined in A181565, with the associated series expansion 5/3 = b + b^2/4 + b^3/(4*19) + b^4/(4*19*94) + .... Cf. A007051. - Peter Bala, Oct 29 2013

Crossrefs

Programs

  • Magma
    [(3*5^n+1)/4: n in [0..30]]; // Vincenzo Librandi, Nov 04 2011
  • Maple
    a[0]:=0:a[1]:=1:for n from 2 to 50 do a[n]:=a[n-1]*5-1 od: seq(a[n], n=1..22); # Zerinvary Lajos, Feb 22 2008
  • Mathematica
    CoefficientList[Series[(1-2x)/((1-5x)(1-x)),{x,0,30}],x] (* or *) LinearRecurrence[{6,-5},{1,4},30] (* Harvey P. Dale, Jul 27 2022 *)

Formula

a(n) = (3*5^n+1)/4.
G.f.: (1-2*x)/((1-5*x)(1-x)).
E.g.f.: (3*exp(5*x) + exp(x))/4.
a(n) = 5*a(n-1)-1 with n>0, a(0)=1. - Vincenzo Librandi, Aug 08 2010
a(n) = 6*a(n-1)-5*a(n-2). - Vincenzo Librandi, Nov 04 2011
a(n) = 5^n - Sum_{i=0..n-1} 5^i. - Bruno Berselli, Jun 20 2013

A083068 7th row of number array A083064.

Original entry on oeis.org

1, 7, 55, 439, 3511, 28087, 224695, 1797559, 14380471, 115043767, 920350135, 7362801079, 58902408631, 471219269047, 3769754152375, 30158033218999, 241264265751991, 1930114126015927, 15440913008127415, 123527304065019319, 988218432520154551, 7905747460161236407
Offset: 0

Views

Author

Paul Barry, Apr 21 2003

Keywords

Comments

Let A be the Hessenberg matrix of order n, defined by: A[1,j]=1, A[i,i]:=10, (i>1), A[i,i-1]=-1, and A[i,j]=0 otherwise. Then, for n>=1, a(n-1)=(-1)^(n-1)*charpoly(A,2). - Milan Janjic, Feb 21 2010

Crossrefs

Programs

Formula

a(n) = (6*8^n+1)/7.
G.f. (1-2*x)/((1-8*x)(1-x)).
E.g.f. (6*exp(8*x)+exp(x))/7.
a(n) = 8*a(n-1)-1 with n>0, a(0)=1. - Vincenzo Librandi, Aug 08 2010
a(n) = 8^n - sum(8^i, i=0..n-1) for n>0. - Bruno Berselli, Jun 20 2013
a(n) = 1 + A125837(n+1). - Alois P. Heinz, May 20 2023

A083069 Main diagonal of number array A083064.

Original entry on oeis.org

1, 2, 11, 94, 1037, 14006, 224695, 4185098, 88888889, 2122152922, 56288512931, 1642813694534, 52332842192581, 1807181134905134, 67253754435399407, 2683521610790452306, 114296029267382825201, 5175920921241202064498
Offset: 0

Views

Author

Paul Barry, Apr 21 2003

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(n (n + 2)^n + 1) / (n + 1), {n, 0, 20}] (* Vincenzo Librandi, Jun 21 2013 *)

Formula

a(n) = (n*(n+2)^n+1)/(n+1).

A083067 6th row of number array A083064.

Original entry on oeis.org

1, 6, 41, 286, 2001, 14006, 98041, 686286, 4804001, 33628006, 235396041, 1647772286, 11534406001, 80740842006, 565185894041, 3956301258286, 27694108808001, 193858761656006, 1357011331592041, 9499079321144286
Offset: 0

Views

Author

Paul Barry, Apr 21 2003

Keywords

Comments

Binomial transform of A052934 - Paul Barry, Apr 30 2003
Let A be the Hessenberg matrix of order n, defined by: A[1,j]=1, A[i,i]:=9, (i>1), A[i,i-1]=-1, and A[i,j]=0 otherwise. Then, for n>=1, a(n-1)=(-1)^(n-1)*charpoly(A,2). [From Milan Janjic, Feb 21 2010]

Crossrefs

Programs

Formula

a(n) = (5*7^n+1)/6.
G.f.: (1-2*x)/((1-7*x)*(1-x)).
E.g.f.: (5*exp(7*x)+exp(x))/6.
a(n) = 7*a(n-1)-1 with a(0)=1. - Vincenzo Librandi, Aug 08 2010
a(n) = 8*a(n-1)-7*a(n-2). - Vincenzo Librandi, Nov 06 2011
a(n) = 7^n - sum(7^i, i=0..n-1) for n>0. [Bruno Berselli, Jun 20 2013]

A083071 First subdiagonal of number array A083064.

Original entry on oeis.org

1, 3, 19, 173, 2001, 28087, 465011, 8888889, 192922993, 4690709411, 126370284195, 3738060156613, 120478742327009, 4203359652212463, 157854212399438371, 6349779403743490289, 272416890591642213921, 12417347368421052631579
Offset: 0

Views

Author

Paul Barry, Apr 21 2003

Keywords

Crossrefs

Formula

a(n) = ((n+1)*(n+3)^n + 1)/(n+2).

A083070 First superdiagonal of number array A083064.

Original entry on oeis.org

1, 5, 43, 469, 6221, 98041, 1797559, 37665881, 888888889, 23343682141, 675462155171, 21356578028941, 732659790696133, 27107717023577009, 1076060070966390511, 45619867383437689201, 2057328526812890853617
Offset: 1

Views

Author

Paul Barry, Apr 21 2003

Keywords

Crossrefs

Formula

a(n) = ((n-1)*(n+1)^n + 1)/n.

A083072 A subdiagonal of number array A083064.

Original entry on oeis.org

1, 4, 29, 286, 3511, 51668, 888889, 17538454, 390892451, 9720791092, 267004296901, 8031916155134, 262709978263279, 9285541905849316, 352765522430193905, 14337731083770642838, 620867368421052631579
Offset: 0

Views

Author

Paul Barry, Apr 21 2003

Keywords

Crossrefs

Formula

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

A083073 A subdiagonal of number array A083064.

Original entry on oeis.org

1, 5, 41, 439, 5741, 88889, 1594405, 32574371, 747753161, 19071735493, 535461077009, 16419373641455, 546208347402901, 19598084579455217, 754617425461612781, 31043368421052631579, 1359040255729886061905
Offset: 0

Views

Author

Paul Barry, Apr 21 2003

Keywords

Crossrefs

Formula

a(n) = ((n+3)*(n+5)^n + 1)/(n+4).

A083074 a(n) = n^3 - n^2 - n - 1.

Original entry on oeis.org

-1, -2, 1, 14, 43, 94, 173, 286, 439, 638, 889, 1198, 1571, 2014, 2533, 3134, 3823, 4606, 5489, 6478, 7579, 8798, 10141, 11614, 13223, 14974, 16873, 18926, 21139, 23518, 26069, 28798, 31711, 34814, 38113, 41614, 45323, 49246, 53389, 57758, 62359, 67198, 72281
Offset: 0

Views

Author

Paul Barry, Apr 21 2003

Keywords

Comments

Values of tribonacci polynomial n^3 - n^2 - n - 1 for n >= 0. - Artur Jasinski, Nov 19 2006

Crossrefs

Apart from initial terms, a column of A083064.

Programs

Formula

a(n) = n^3 + 5*n^2 + 7*n + 1 = (n*(n + 2)^3 + 1)/(n + 1) [with a different offset].
G.f.: (2*x^3+3*x^2+2*x-1)/(x-1)^4. - Alois P. Heinz, Jan 25 2023
From Elmo R. Oliveira, Aug 08 2025: (Start)
E.g.f.: exp(x)*(-1 - x + 2*x^2 + x^3).
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)

Extensions

Simpler definition from Alonso del Arte, Sep 16 2004
Showing 1-10 of 12 results. Next