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 1-4 of 4 results.

A001611 a(n) = Fibonacci(n) + 1.

Original entry on oeis.org

1, 2, 2, 3, 4, 6, 9, 14, 22, 35, 56, 90, 145, 234, 378, 611, 988, 1598, 2585, 4182, 6766, 10947, 17712, 28658, 46369, 75026, 121394, 196419, 317812, 514230, 832041, 1346270, 2178310, 3524579, 5702888, 9227466, 14930353, 24157818, 39088170, 63245987, 102334156
Offset: 0

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Keywords

Comments

a(0) = 1, a(1) = 2 then the largest number such that a triangle is constructible with three successive terms as sides. - Amarnath Murthy, Jun 03 2003
a(n+2) = A^(n)B(1), n>=0, with compositions of Wythoff's complementary A(n):=A000201(n) and B(n)=A001950(n) sequences. See the W. Lang link under A135817 for the Wythoff representation of numbers (with A as 1 and B as 0 and the argument 1 omitted). E.g., 2=`0`, 3=`10`, 4=`110`, 6=`1110`, ..., in Wythoff code.
The first-difference sequence is the Fibonacci sequence (A000045). - Roland Schroeder (florola(AT)gmx.de), Aug 05 2010
2 and 3 are the only primes in this sequence.
a(n) is the number of 1 X n nonogram puzzles which can be solved uniquely. See A242876 for puzzle definition. - Lior Manor, Jan 23 2022

References

  • G. Everest, A. van der Poorten, I. Shparlinski and T. Ward, Recurrence Sequences, Amer. Math. Soc., 2003; see esp. p. 255.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Haskell
    a001611 = (+ 1) . a000045
    a001611_list = 1 : 2 : map (subtract 1)
                           (zipWith (+) a001611_list $ tail a001611_list)
    -- Reinhard Zumkeller, Jul 30 2013
  • Magma
    [Fibonacci(n)+1: n in [1..37]]; // Bruno Berselli, Jul 26 2011
    
  • Maple
    A001611:=-(-1+2*z**2)/(z-1)/(z**2+z-1); # Simon Plouffe in his 1992 dissertation
    with(combinat): seq((fibonacci(n)+1), n=0..35);
  • Mathematica
    a[0] = 1; a[1] = 2; a[n_] := a[n] = a[n-2] + a[n-1] - 1; Table[ a[n], {n, 0, 40} ]
    Fibonacci[Range[0,50]]+1  (* Harvey P. Dale, Mar 23 2011 *)
  • PARI
    a(n)=fibonacci(n)+1 \\ Charles R Greathouse IV, Jul 25 2011
    

Formula

G.f.: (1-2*x^2)/(1-2*x+x^3).
a(n) = 2*a(n-1) - a(n-3). - Tanya Khovanova, Jul 13 2007
a(0) = 1, a(1) = 2, a(n) = a(n - 2) + a(n - 1) - 1.
F(4*n) + 1 = F(2*n-1)*L(2*n+1); F(4*n+1) + 1 = F(2*n+1)*L(2*n); F(4*n+2) + 1 = F(2*n+2)*L(2*n); F(4*n+3) + 1 = F(2*n+1)*L(2*n+2) where F(n)=Fibonacci(n) and L(n)=Lucas(n). - R. K. Guy, Feb 27 2003
a(1) = 2; a(n+1)=floor(a(n)*(sqrt(5)+1)/2). - Roland Schroeder (florola(AT)gmx.de), Aug 05 2010
a(n) = Sum_{k=0..n+1} Fibonacci(k-3). - Ehren Metcalfe, Apr 15 2019
Product_{n>=1} (1 - (-1)^n/a(n)) = sin(3*Pi/10) (A019863). - Amiram Eldar, Nov 28 2024

A002062 a(n) = Fibonacci(n) + n.

Original entry on oeis.org

0, 2, 3, 5, 7, 10, 14, 20, 29, 43, 65, 100, 156, 246, 391, 625, 1003, 1614, 2602, 4200, 6785, 10967, 17733, 28680, 46392, 75050, 121419, 196445, 317839, 514258, 832070, 1346300, 2178341, 3524611, 5702921, 9227500, 14930388, 24157854, 39088207, 63246025
Offset: 0

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Let A006355(n+4)_0%20-%20A066982(n+1)_1%20(conjecture);%20(a(n))%20=%20em%5BK*%20%5Dseq(%20.25'i%20-%20.25'j%20-%20.25'k%20-%20.25i'%20+%20.25j'%20-%20.75k'%20-%20.25'ii'%20-%20.25'jj'%20-%20.25'kk'%20-%20.25'ij'%20-%20.25'ik'%20-%20.75'ji'%20+%20.25'jk'%20-%20.25'ki'%20-%20.75'kj'%20+%20.75e),%20apart%20from%20initial%20term.%20-%20_Creighton%20Dement">x indicate the sequence offset. Then a(n+2)_0 = A006355(n+4)_0 - A066982(n+1)_1 (conjecture); (a(n)) = em[K* ]seq( .25'i - .25'j - .25'k - .25i' + .25j' - .75k' - .25'ii' - .25'jj' - .25'kk' - .25'ij' - .25'ik' - .75'ji' + .25'jk' - .25'ki' - .75'kj' + .75e), apart from initial term. - _Creighton Dement, Nov 19 2004

References

  • R. Honsberger, Ingenuity in Math., Random House, 1970, p. 96.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • GAP
    List([0..50], n-> Fibonacci(n)+n); # G. C. Greubel, Jul 09 2019
  • Haskell
    a002062 n = a000045 n + toInteger n
    a002062_list = 0 : 2 : 3 : (map (subtract 1) $
       zipWith (-) (map (* 2) $ drop 2 a002062_list) a002062_list)
    -- Reinhard Zumkeller, Oct 03 2012
    
  • Magma
    [Fibonacci(n)+n: n in [0..50]]; // G. C. Greubel, Jul 09 2019
    
  • Maple
    a:= n-> combinat[fibonacci](n)+n: seq(a(n), n=0..50); # Zerinvary Lajos, Mar 20 2008
  • Mathematica
    Table[Fibonacci[n]+n,{n,0,50}] (* Harvey P. Dale, Jul 27 2011 *)
  • MuPAD
    numlib::fibonacci(n)+n $ n = 0..50; // Zerinvary Lajos, May 08 2008
    
  • PARI
    a(n)=fibonacci(n) + n \\ Charles R Greathouse IV, Oct 03 2016
    
  • Sage
    [fibonacci(n)+n for n in (0..50)] # G. C. Greubel, Jul 09 2019
    

Formula

G.f.: x*(-2+3*x) / ( (x^2+x-1)*(x-1)^2 ). - Simon Plouffe in his 1992 dissertation
From Wolfdieter Lang: (Start)
Convolution of natural numbers n >= 1 with Fibonacci numbers F(k), k >= -3, (F(-k)=(-1)^(k+1)*F(k));
G.f.: x*(2-3*x)/((1-x-x^2)*(1-x)^2). (End)
a(n) = 2*a(n-1) - a(n-3) - 1. - Kieren MacMillan, Nov 08 2008
a(n) = 3*a(n-1) - 2*a(n-2) - a(n-3) + a(n-4). - Emmanuel Vantieghem, May 19 2016
E.g.f.: 2*exp(x/2)*sinh(sqrt(5)*x/2)/sqrt(5) + x*exp(x). - Ilya Gutkovskiy, Apr 11 2017

A212272 a(n) = Fibonacci(n) + n^3.

Original entry on oeis.org

0, 2, 9, 29, 67, 130, 224, 356, 533, 763, 1055, 1420, 1872, 2430, 3121, 3985, 5083, 6510, 8416, 11040, 14765, 20207, 28359, 40824, 60192, 90650, 138969, 216101, 339763, 538618, 859040, 1376060, 2211077, 3560515, 5742191, 9270340, 14977008, 24208470, 39143041
Offset: 0

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Author

Bruno Berselli, May 09 2012

Keywords

Crossrefs

Programs

  • Magma
    [Fibonacci(n)+n^3: n in [0..38]];
  • Mathematica
    Table[Fibonacci[n] + n^3, {n, 0, 38}]
  • PARI
    for(n=0, 38, print1(fibonacci(n)+n^3", "));
    

Formula

G.f.: x*(2-x+2*x^2-9*x^3)/((1-x-x^2)*(1-x)^4).

A179992 a(n) = a(n-1) + a(n-2) + n^2 for n >= 3, a(1)=2, and a(2)=5.

Original entry on oeis.org

2, 5, 16, 37, 78, 151, 278, 493, 852, 1445, 2418, 4007, 6594, 10797, 17616, 28669, 46574, 75567, 122502, 198469, 321412, 520365, 842306, 1363247, 2206178, 3570101, 5777008, 9347893, 15125742, 24474535, 39601238, 64076797, 103679124
Offset: 1

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Author

Carmine Suriano, Aug 05 2010

Keywords

Comments

Each term is the sum of the previous two plus the square of its index.

Examples

			a(5) = a(4)+a(3)+5^2 = 16+37+25 = 78.
		

Crossrefs

Cf. A160536, A163250. - Bruno Berselli, Aug 25 2010

Formula

a(n) = F(n-2) + (Sum_{i=1..n} i^2) + Sum_{k=0..n-2} F(k)*Sum_{j=0..n-k-1} j^2, where F(i) is the i-th Fibonacci number. [Corrected by Jason Yuen, Apr 09 2025]
G.f.: x*(x^4-4*x^3+6*x^2-3*x+2)/((1-x-x^2)*(1-x)^3). [Corrected by Bruno Berselli, Aug 25 2010 and R. J. Mathar, Oct 18 2010]
Limiting ratio a(n+1)/a(n) = Phi = 1.618038...
a(n) = 2*A022095(n+2)-6*n-13-n^2. - R. J. Mathar, Aug 06 2010
a(n)-4*a(n-1)+5*a(n-2)-a(n-3)-2*a(n-4)+a(n-5) = 0 with n>5. - Bruno Berselli, Aug 25 2010
Showing 1-4 of 4 results.