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 1-3 of 3 results.

A099213 a(n) = a(n-1)+a(n-2)+3a(n-3), with a(0)=a(1)=a(2)=1.

Original entry on oeis.org

1, 1, 1, 5, 9, 17, 41, 85, 177, 385, 817, 1733, 3705, 7889, 16793, 35797, 76257, 162433, 346081, 737285, 1570665, 3346193, 7128713, 15186901, 32354193, 68927233, 146842129, 312831941, 666455769, 1419814097, 3024765689, 6443947093
Offset: 0

Views

Author

Paul Barry, Oct 06 2004

Keywords

Comments

Binomial transform is A099214. Binomial transform of A099212.

Crossrefs

Programs

  • PARI
    Vec((1-x^2)/(1-x-x^2-3*x^3) + O(x^30)) \\ Michel Marcus, Aug 31 2022
  • Sage
    from sage.combinat.sloane_functions import recur_gen3; it = recur_gen3(1,1,1,1,1,3); [next(it) for i in range(32)] # Zerinvary Lajos, Jun 25 2008
    

Formula

G.f.: (1-x^2)/(1-x-x^2-3*x^3). [corrected by Michel Marcus, Aug 31 2022]

A099215 a(n)=4a(n-1)-4a(n-2)+3a(n-3).

Original entry on oeis.org

1, 2, 4, 11, 34, 104, 313, 938, 2812, 8435, 25306, 75920, 227761, 683282, 2049844, 6149531, 18448594, 55345784, 166037353, 498112058, 1494336172, 4483008515, 13449025546, 40347076640, 121041229921, 363123689762, 1089371069284
Offset: 0

Views

Author

Paul Barry, Oct 06 2004

Keywords

Crossrefs

Cf. A099214.

Programs

  • Mathematica
    LinearRecurrence[{4,-4,3},{1,2,4},30] (* Harvey P. Dale, Mar 02 2013 *)

Formula

G.f.: (1-2x)/((1-2x)^2-3x^3); a(n)=sum{k=0..floor(n/3), binomial(n-k, 2k)3^k*2^(n-3k)}.
a{x}=1/7(-Cos[(Pi*x)/3]+Cosh[x*Log[3]]+3*Sqrt[3]*Sin[(Pi*x)/3]+Sinh[x*Log[3]]) - Harvey P. Dale, Mar 02 2013

A099216 a(n)=4a(n-1)-4a(n-2)+2a(n-3).

Original entry on oeis.org

1, 2, 4, 10, 28, 80, 228, 648, 1840, 5224, 14832, 42112, 119568, 339488, 963904, 2736800, 7770560, 22062848, 62642752, 177860736, 504997632, 1433833088, 4071063296, 11558916096, 32819077376, 93182771712, 264572609536
Offset: 0

Views

Author

Paul Barry, Oct 06 2004

Keywords

Comments

Binomial transform of tribonacci numbers A000213.

Crossrefs

Formula

G.f.: (1-2x)/((1-2x)^2-2x^3); a(n)=sum{k=0..floor(n/3), binomial(n-k, 2k)2^k*2^(n-3k)}.
Showing 1-3 of 3 results.