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.

User: Geoff Ahiakwo

Geoff Ahiakwo's wiki page.

Geoff Ahiakwo has authored 5 sequences.

A255875 a(n) = Fibonacci(n+2) + n - 2.

Original entry on oeis.org

1, 3, 6, 10, 16, 25, 39, 61, 96, 152, 242, 387, 621, 999, 1610, 2598, 4196, 6781, 10963, 17729, 28676, 46388, 75046, 121415, 196441, 317835, 514254, 832066, 1346296, 2178337, 3524607, 5702917, 9227496, 14930384, 24157850, 39088203, 63246021, 102334191, 165580178, 267914334
Offset: 1

Author

Geoff Ahiakwo, Mar 08 2015

Keywords

Programs

  • Mathematica
    Array[Fibonacci[# + 2] + # - 2 &, 30] (* Michael De Vlieger, Jul 10 2015 *)
  • PARI
    main(size)={return( vector(size,n,fibonacci(n+2)+n-2));} /* Anders Hellström, Jul 11 2015 */

Formula

G.f.: x*(-1+x^2+x^3) / ( (x^2+x-1)*(x-1)^2 ). - R. J. Mathar, Jul 10 2015
a(n) = A232896(n+1)-2. - R. J. Mathar, Jul 10 2015

Extensions

Terms a(31) and beyond from Andrew Howroyd, Dec 23 2019

A166876 a(n) = a(n-1) + Fibonacci(n), a(1)=1983.

Original entry on oeis.org

1983, 1984, 1986, 1989, 1994, 2002, 2015, 2036, 2070, 2125, 2214, 2358, 2591, 2968, 3578, 4565, 6162, 8746, 12927, 19692, 30638, 48349, 77006, 123374, 198399, 319792, 516210, 834021, 1348250, 2180290, 3526559, 5704868, 9229446, 14932333, 24159798
Offset: 1

Author

Geoff Ahiakwo, Oct 22 2009

Keywords

Comments

Starting at some a(1)=s and creating further terms with the recurrence a(n)=a(n-1)+A000045(n) defines a family of sequences with recurrences a(n)= 2*a(n-1) -a(n-3).
The generating functions are x*( s+(1-s)*x+(1-s)*x^2 )/((1-x) * (1-x-x^2)).
The terms are a(n) = A000045(n+2)+s-2 = s + A001911(n-1) = (2*s+1+k)/2 where k=A166863(n-1), n>=1.
Examples: Up to offsets, s=1 yields A000071, s=2 yields A000045 shifted left thrice, s=3 yields A001611 shifted left thrice, s=4 yields A018910.
I appreciate the editing by R. J. Mathar. However I would like further analysis of the following formula. The sequence which I call GAP can have any integer as its first term, not just 1983. Thus a(1) can be 0, 1, 2, 3,... Then a(2) is always a(1)+ 1, while a(3) is a(1) + k(n)/2; where k(n) = k(n-2)+ k(n-1)+4 (This is a separate sequence submitted for consideration). [Geoff Ahiakwo, Nov 19 2009]

Examples

			For s=1983, n=3, we have k= A166863(2)= 5, a(3) = (2s+1+k)/2 = (2*1983+1+5)/2 = 1986.
For n=3, a(3)= a(1)+ k(3)/2 = a(1)+ [K(3-2)+ k(3-1)]/2 + 2 = a(1)+ 1 + 2 thus if a(1)is 0, a(3)= 3; if a(1)= 5, a(3)= 8; if a(1)=1983, a(3)= 1986, etc. [_Geoff Ahiakwo_, Nov 19 2009]
		

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{2, 0, -1}, {1983, 1984, 1986}, 100] (* G. C. Greubel, May 27 2016 *)

Formula

a(n) = 2*a(n-1) - a(n-3).
G.f.: x*(-1983 + 1982*x + 1982*x^2)/((1-x)*(x^2+x-1)).
Let a(n)= a(1)+ k(n)/2, then G.f.: k(n)= k(n-2)+ k(n-1) + 4. - Geoff Ahiakwo, Nov 19 2009

Extensions

Definition and comments edited by R. J. Mathar, Oct 26 2009

A166863 a(1)= 1; a(2)= 5; thereafter a(n)= a(n-1) + a(n-2) + 5.

Original entry on oeis.org

1, 5, 11, 21, 37, 63, 105, 173, 283, 461, 749, 1215, 1969, 3189, 5163, 8357, 13525, 21887, 35417, 57309, 92731, 150045, 242781, 392831, 635617, 1028453, 1664075, 2692533, 4356613, 7049151, 11405769, 18454925, 29860699, 48315629, 78176333, 126491967
Offset: 1

Author

Geoff Ahiakwo, Oct 22 2009

Keywords

Examples

			a(3) = 5 + 1 + 5 = 11.
		

Crossrefs

Programs

  • Haskell
    a166863 n = a166863_list !! (n-1)
    a166863_list = 1 : zipWith (+) a166863_list (drop 3 $ map (* 2) a000045_list)
    -- Reinhard Zumkeller, Nov 17 2013
  • Mathematica
    2 * Fibonacci[Range[4,4! ]] - 5 (* Vladimir Joseph Stephan Orlovsky, Mar 19 2010 *)
    RecurrenceTable[{a[1]==1,a[2]==5,a[n]==a[n-1]+a[n-2]+5},a,{n,40}] (* or *) LinearRecurrence[{2,0,-1},{1,5,11},40] (* Harvey P. Dale, Jan 29 2021 *)

Formula

a(n) = A154691(n) - 2 = 2*A000045(n+3) - 5. - R. J. Mathar, Oct 26 2009
From R. J. Mathar, Oct 26 2009: (Start)
a(n) = 2*a(n-1) - a(n-3).
G.f: x*(1+3*x+x^2)/((x-1)* (x^2+x-1)). (End)
a(n+1) = a(n) + 2*A000045(n+2). - Reinhard Zumkeller, Nov 17 2013

Extensions

Missing value for a(29) inserted by Reinhard Zumkeller, Nov 17 2013

A169622 a(n) = a(n-1) + Fibonacci(n), a(1)=5.

Original entry on oeis.org

5, 6, 8, 11, 16, 24, 37, 58, 92, 147, 236, 380, 613, 990, 1600, 2587, 4184, 6768, 10949, 17714, 28660, 46371, 75028, 121396, 196421, 317814, 514232, 832043, 1346272, 2178312, 3524581, 5702890, 9227468, 14930355, 24157820, 39088172, 63245989, 102334158
Offset: 1

Author

Geoff Ahiakwo, Dec 03 2009

Keywords

Examples

			n=2: a(1)+Fibonacci(2) = 5+1 = 6.
n=3: a(2)+Fibonacci(3) = 6+2 = 8.
		

Crossrefs

Programs

  • Magma
    [ n eq 1 select 5 else Self(n-1)+Fibonacci(n): n in [1..40] ];  // Klaus Brockhaus, Jan 31 2011
    
  • Mathematica
    RecurrenceTable[{a[1]==5,a[n]==a[n-1]+Fibonacci[n]},a[n],{n,40}] (* or *) LinearRecurrence[{2,0,-1},{5,6,8},40] (* Harvey P. Dale, Jul 20 2011 *)
  • PARI
    Vec((5 - 4*x - 4*x^2) / ((1 - x)*(1 - x - x^2)) + O(x^40)) \\ Colin Barker, Apr 20 2017

Formula

a(n) = 5 + A168193(n)/2.
a(n) = 2*a(n-1) - a(n-3) = 3 + A000045(n+2). - R. J. Mathar Dec 04 2009
G.f.: x*(-5+4*x+4*x^2) / ((1-x)*(x^2+x-1)). - R. J. Mathar Dec 04 2009
a(n) = 3 + (2^(-1-n)*((1-sqrt(5))^n*(-3+sqrt(5)) + (1+sqrt(5))^n*(3+sqrt(5)))) / sqrt(5). - Colin Barker, Apr 20 2017

A168193 a(n) = a(n-1) + a(n-2) + 4, with a(0)=0, a(1)=2.

Original entry on oeis.org

0, 2, 6, 12, 22, 38, 64, 106, 174, 284, 462, 750, 1216, 1970, 3190, 5164, 8358, 13526, 21888, 35418, 57310, 92732, 150046, 242782, 392832, 635618, 1028454, 1664076, 2692534, 4356614, 7049152, 11405770, 18454926, 29860700, 48315630, 78176334, 126491968
Offset: 0

Author

Geoff Ahiakwo, Nov 19 2009

Keywords

Programs

Formula

From R. J. Mathar, Nov 22 2009: (Start)
a(n)= 2*a(n-1) - a(n-3) = 2*A001911(n).
G.f.: 2*x*(1+x)/((x-1)*(x^2+x-1)). (End)
a(n) = a(n-1) + 2*Fibonacci(n+1), with a(0)=0. - Taras Goy, Mar 24 2019
E.g.f.: 4*exp(x/2)*(5*cosh(sqrt(5)*x/2) + 2*sqrt(5)*sinh(sqrt(5)*x/2))/5 - 4*exp(x). - Stefano Spezia, Oct 14 2022
a(n) = A019274(n+1)+A019274(n+2). - R. J. Mathar, Jul 07 2023

Extensions

Definition replaced by recurrence from R. J. Mathar, Nov 23 2009