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 1-8 of 8 results.

A101220 a(n) = Sum_{k=0..n} Fibonacci(n-k)*n^k.

Original entry on oeis.org

0, 1, 3, 14, 91, 820, 9650, 140601, 2440317, 49109632, 1123595495, 28792920872, 816742025772, 25402428294801, 859492240650847, 31427791175659690, 1234928473553777403, 51893300561135516404, 2322083099525697299278
Offset: 0

Views

Author

Ross La Haye, Dec 14 2004

Keywords

Comments

In what follows a(i,j,k) denotes a three-dimensional array, the terms a(n) are defined as a(n,n,n) in that array. - Joerg Arndt, Jan 03 2021
Previous name was: Three-dimensional array: a(i,j,k) = expansion of x*(1 + (i-j)*x)/((1-j*x)*(1-x-x^2)), read by a(n,n,n).
a(i,j,k) = the k-th value of the convolution of the Fibonacci numbers (A000045) with the powers of i = Sum_{m=0..k} a(i-1,j,m), both for i = j and i > 0; a(i,j,k) = a(i-1,j,k) + a(j,j,k-1), for i,k > 0; a(i,1,k) = Sum_{m=0..k} a(i-1,0,m), for i > 0. With F = Fibonacci and L = Lucas, then a(1,1,k) = F(k+2) - 1; a(2,1,k) = F(k+3) - 2; a(3,1,k) = L(k+2) - 3; a(4,1,k) = 4*F(k+1) + F(k) - 4; a(1,2,k) = 2^k - F(k+1); a(2,2,k) = 2^(k+1) - F(k+3); a(3,2,k) = 3(2^k - F(k+2)) + F(k); a(4,2,k) = 2^(k+2) - F(k+4) - F(k+2); a(1,3,k) = (3^k + L(k-1))/5, for k > 0; a(2,3,k) = (2 * 3^k - L(k)) /5, for k > 0; a(3,3,k) = (3^(k+1) - L(k+2))/5; a(4,3,k) = (4 * 3^k - L(k+2) - L(k+1))/5, etc..

Examples

			a(1,3,3) = 6 because a(1,3,0) = 0, a(1,3,1) = 1, a(1,3,2) = 2 and 4*2 - 2*1 - 3*0 = 6.
		

Crossrefs

a(0, j, k) = A000045(k).
a(1, 2, k+1) - a(1, 2, k) = A099036(k).
a(3, 2, k+1) - a(3, 2, k) = A104004(k).
a(4, 2, k+1) - a(4, 2, k) = A027973(k).
a(1, 3, k+1) - a(1, 3, k) = A099159(k).
a(i, 0, k) = A109754(i, k).
a(i, i+1, 3) = A002522(i+1).
a(i, i+1, 4) = A071568(i+1).
a(2^i-2, 0, k+1) = A118654(i, k), for i > 0.
Sequences of the form a(n, 0, k): A000045(k+1) (n=1), A000032(k) (n=2), A000285(k-1) (n=3), A022095(k-1) (n=4), A022096(k-1) (n=5), A022097(k-1) (n=6), A022098(k-1) (n=7), A022099(k-1) (n=8), A022100(k-1) (n=9), A022101(k-1) (n=10), A022102(k-1) (n=11), A022103(k-1) (n=12), A022104(k-1) (n=13), A022105(k-1) (n=14), A022106(k-1) (n=15), A022107(k-1) (n=16), A022108(k-1) (n=17), A022109(k-1) (n=18), A022110(k-1) (n=19), A088209(k-2) (n=k-2), A007502(k) (n=k-1), A094588(k) (n=k).
Sequences of the form a(1, n, k): A000071(k+2) (n=1), A027934(k-1) (n=2), A098703(k) (n=3).
Sequences of the form a(2, n, k): A001911(k) (n=1), A008466(k+1) (n=2), A106517(k-1) (n=3).
Sequences of the form a(3, n, k): A027961(k) (n=1), A094688(k) (n=3).
Sequences of the form a(4, n, k): A053311(k-1) (n=1), A027974(k-1) (n=2).

Programs

  • Magma
    A101220:= func< n | (&+[n^k*Fibonacci(n-k): k in [0..n]]) >;
    [A101220(n): n in [0..30]]; // G. C. Greubel, Jun 01 2025
    
  • Mathematica
    Join[{0}, Table[Sum[Fibonacci[n-k]*n^k, {k, 0, n}], {n, 1, 20}]] (* Vaclav Kotesovec, Jan 03 2021 *)
  • PARI
    a(n)=sum(k=0,n,fibonacci(n-k)*n^k) \\ Joerg Arndt, Jan 03 2021
    
  • SageMath
    def A101220(n): return sum(n^k*fibonacci(n-k) for k in range(n+1))
    print([A101220(n) for n in range(31)]) # G. C. Greubel, Jun 01 2025

Formula

a(i, j, 0) = 0, a(i, j, 1) = 1, a(i, j, 2) = i+1; a(i, j, k) = ((j+1)*a(i, j, k-1)) - ((j-1)*a(i, j, k-2)) - (j*a(i, j, k-3)), for k > 2.
a(i, j, k) = Fibonacci(k) + i*a(j, j, k-1), for i, k > 0.
a(i, j, k) = (Phi^k - (-Phi)^-k + i(((j^k - Phi^k) / (j - Phi)) - ((j^k - (-Phi)^-k) / (j - (-Phi)^-1)))) / sqrt(5), where Phi denotes the golden mean/ratio (A001622).
i^k = a(i-1, i, k) + a(i-2, i, k+1).
A104161(k) = Sum_{m=0..k} a(k-m, 0, m).
a(i, j, 0) = 0, a(i, j, 1) = 1, a(i, j, 2) = i+1, a(i, j, 3) = i*(j+1) + 2; a(i, j, k) = (j+2)*a(i, j, k-1) - 2*j*a(i, j, k-2) - a(i, j, k-3) + j*a(i, j, k-4), for k > 3. a(i, j, 0) = 0, a(i, j, 1) = 1; a(i, j, k) = a(i, j, k-1) + a(i, j, k-2) + i * j^(k-2), for k > 1.
G.f.: x*(1 + (i-j)*x)/((1-j*x)*(1-x-x^2)).
a(n, n, n) = Sum_{k=0..n} Fibonacci(n-k) * n^k. - Ross La Haye, Jan 14 2006
Sum_{m=0..k} binomial(k,m)*(i-1)^m = a(i-1,i,k) + a(i-2,i,k+1), for i > 1. - Ross La Haye, May 29 2006
From Ross La Haye, Jun 03 2006: (Start)
a(3, 3, k+1) - a(3, 3, k) = A106517(k).
a(1, 1, k) = A001924(k) - A001924(k-1), for k > 0.
a(2, 1, k) = A001891(k) - A001891(k-1), for k > 0.
a(3, 1, k) = A023537(k) - A023537(k-1), for k > 0.
Sum_{j=0..i+1} a(i-j+1, 0, j) - Sum_{j=0..i} a(i-j, 0, j) = A001595(i). (End)
a(i,j,k) = a(j,j,k) + (i-j)*a(j,j,k-1), for k > 0.
a(n) ~ n^(n-1). - Vaclav Kotesovec, Jan 03 2021

Extensions

New name from Joerg Arndt, Jan 03 2021

A093645 (10,1) Pascal triangle.

Original entry on oeis.org

1, 10, 1, 10, 11, 1, 10, 21, 12, 1, 10, 31, 33, 13, 1, 10, 41, 64, 46, 14, 1, 10, 51, 105, 110, 60, 15, 1, 10, 61, 156, 215, 170, 75, 16, 1, 10, 71, 217, 371, 385, 245, 91, 17, 1, 10, 81, 288, 588, 756, 630, 336, 108, 18, 1, 10, 91, 369, 876, 1344, 1386, 966, 444, 126, 19, 1
Offset: 0

Views

Author

Wolfdieter Lang, Apr 22 2004

Keywords

Comments

The array F(10;n,m) gives in the columns m >= 1 the figurate numbers based on A017281, including the 12-gonal numbers A051624 (see the W. Lang link).
This is the tenth member, d=10, in the family of triangles of figurate numbers, called (d,1) Pascal triangles: A007318 (Pascal), A029653, A093560-5 and A093644 for d=1..9.
This is an example of a Riordan triangle (see A093560 for a comment and A053121 for a comment and the 1991 Shapiro et al. reference on the Riordan group). Therefore the o.g.f. for the row polynomials p(n,x) := Sum_{m=0..n} a(n,m)*x^m is G(z,x) = (1+9*z)/(1-(1+x)*z).
The SW-NE diagonals give A022100(n-1) = Sum_{k=0..ceiling((n-1)/2)} a(n-1-k, k), n >= 1, with n=0 value 9. Observation by Paul Barry, Apr 29 2004. Proof via recursion relations and comparison of inputs.

Examples

			Triangle begins
   1;
  10,  1;
  10, 11,  1;
  10, 21, 12,  1;
  ...
		

References

  • Kurt Hawlitschek, Johann Faulhaber 1580-1635, Veroeffentlichung der Stadtbibliothek Ulm, Band 18, Ulm, Germany, 1995, Ch. 2.1.4. Figurierte Zahlen.
  • Ivo Schneider: Johannes Faulhaber 1580-1635, Birkhäuser, Basel, Boston, Berlin, 1993, ch. 5, pp. 109-122.

Crossrefs

Row sums: 1 for n=0 and A005015(n-1), n >= 1, alternating row sums are 1 for n=0, 9 for n=2 and 0 otherwise.
The column sequences give for m=1..9: A017281, A051624 (12-gonal), A007587, A051799, A051880, A050406, A052254, A056125, A093646.

Programs

  • Haskell
    a093645 n k = a093645_tabl !! n !! k
    a093645_row n = a093645_tabl !! n
    a093645_tabl = [1] : iterate
                   (\row -> zipWith (+) ([0] ++ row) (row ++ [0])) [10, 1]
    -- Reinhard Zumkeller, Aug 31 2014
  • Mathematica
    t[0, 0] = 1; t[n_, k_] := Binomial[n, k] + 9*Binomial[n-1, k]; Table[t[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jul 05 2013, after Philippe Deléham *)

Formula

a(n, m) = F(10;n-m, m) for 0 <= m <= n, else 0, with F(10;0, 0)=1, F(10;n, 0)=10 if n >= 1 and F(10;n, m):=(10*n+m)*binomial(n+m-1, m-1)/m if m >= 1.
Recursion: a(n, m)=0 if m > n, a(0, 0)=1; a(n, 0)=10 if n >= 1; a(n, m) = a(n-1, m) + a(n-1, m-1).
G.f. column m (without leading zeros): (1+9*x)/(1-x)^(m+1), m >= 0.
T(n, k) = C(n, k) + 9*C(n-1, k). - Philippe Deléham, Aug 28 2005
exp(x) * e.g.f. for row n = e.g.f. for diagonal n. For example, for n = 3 we have exp(x)*(10 + 21*x + 12*x^2/2! + x^3/3!) = 10 + 31*x + 64*x^2/2! + 110*x^3/3! + 170*x^4/4! + .... The same property holds more generally for Riordan arrays of the form ( f(x), x/(1 - x) ). - Peter Bala, Dec 22 2014

A109754 Matrix defined by: a(i,0) = 0, a(i,j) = i*Fibonacci(j-1) + Fibonacci(j), for j > 0; read by ascending antidiagonals.

Original entry on oeis.org

0, 0, 1, 0, 1, 1, 0, 1, 2, 2, 0, 1, 3, 3, 3, 0, 1, 4, 4, 5, 5, 0, 1, 5, 5, 7, 8, 8, 0, 1, 6, 6, 9, 11, 13, 13, 0, 1, 7, 7, 11, 14, 18, 21, 21, 0, 1, 8, 8, 13, 17, 23, 29, 34, 34, 0, 1, 9, 9, 15, 20, 28, 37, 47, 55, 55, 0, 1, 10, 10, 17, 23, 33, 45, 60, 76, 89, 89
Offset: 0

Views

Author

Ross La Haye, Aug 11 2005; corrected Apr 14 2006

Keywords

Comments

Lower triangular version is at A117501. - Ross La Haye, Apr 12 2006

Examples

			Table starts:
[0] 0, 1,  1,  2,  3,  5,  8, 13,  21,  34, ...
[1] 0, 1,  2,  3,  5,  8, 13, 21,  34,  55, ...
[2] 0, 1,  3,  4,  7, 11, 18, 29,  47,  76, ...
[3] 0, 1,  4,  5,  9, 14, 23, 37,  60,  97, ...
[4] 0, 1,  5,  6, 11, 17, 28, 45,  73, 118, ...
[5] 0, 1,  6,  7, 13, 20, 33, 53,  86, 139, ...
[6] 0, 1,  7,  8, 15, 23, 38, 61,  99, 160, ...
[7] 0, 1,  8,  9, 17, 26, 43, 69, 112, 181, ...
[8] 0, 1,  9, 10, 19, 29, 48, 77, 125, 202, ...
[9] 0, 1, 10, 11, 21, 32, 53, 85, 138, 223, ...
		

Crossrefs

Rows: A000045(j); A000045(j+1), for j > 0; A000032(j), for j > 0; A000285(j-1), for j > 0; A022095(j-1), for j > 0; A022096(j-1), for j > 0; A022097(j-1), for j > 0. Diagonals: a(i, i) = A094588(i); a(i, i+1) = A007502(i+1); a(i, i+2) = A088209(i); Sum[a(i-j, j), {j=0...i}] = A104161(i). a(i, j) = A101220(i, 0, j).
Rows 7 - 19: A022098(j-1), for j > 0; A022099(j-1), for j > 0; A022100(j-1), for j > 0; A022101(j-1), for j > 0; A022102(j-1), for j > 0; A022103(j-1), for j > 0; A022104(j-1), for j > 0; A022106(j-1), for j > 0; A022107(j-1), for j > 0; A022108(j-1), for j > 0; A022109(j-1), for j > 0; A022110(j-1), for j > 0.
a(2^i-2, j+1) = A118654(i, j), for i > 0.
Cf. A117501.

Programs

  • Maple
    A := (n, k) -> ifelse(k = 0, 0,
          n*combinat:-fibonacci(k-1) + combinat:-fibonacci(k)):
    seq(seq(A(n - k, k), k = 0..n), n = 0..6); # Peter Luschny, May 28 2022
  • Mathematica
    T[n_, 0]:= 0; T[n_, 1]:= 1; T[n_, 2]:= n - 1; T[n_, 3]:= n - 1; T[n_, n_]:= Fibonacci[n]; T[n_, k_]:= T[n, k] = T[n - 1, k - 1] + T[n - 2, k - 2]; Table[T[n, k], {n, 0, 15}, {k, 0, n}] (* G. C. Greubel, Jan 07 2017 *)

Formula

a(i, 0) = 0, a(i, j) = i*Fibonacci(j-1) + Fibonacci(j), for j > 0.
a(i, 0) = 0, a(i, 1) = 1, a(i, 2) = i+1, a(i, j) = a(i, j-1) + a(i, j-2), for j > 2.
G.f.: (x*(1 + ix))/(1 - x - x^2).
Sum_{j=0..i+1} a(i-j+1, j) - Sum_{j=0..i} a(i-j, j) = A001595(i). - Ross La Haye, Jun 03 2006

Extensions

More terms from G. C. Greubel, Jan 07 2017

A127830 a(n) = Sum_{k=0..n} (binomial(floor(k/2),n-k) mod 2).

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 2, 3, 3, 3, 2, 2, 3, 2, 3, 5, 5, 4, 4, 5, 4, 3, 3, 3, 4, 4, 3, 4, 5, 3, 5, 8, 8, 7, 6, 7, 7, 5, 6, 8, 7, 6, 5, 5, 5, 4, 4, 5, 6, 5, 5, 7, 6, 4, 5, 6, 7, 7, 5, 6, 8, 5, 8, 13, 13, 11, 10, 12, 11, 8, 9, 11, 11, 10, 8, 9, 10, 7, 9, 13, 12
Offset: 0

Views

Author

Paul Barry, Feb 01 2007

Keywords

Comments

Row sums of number triangle A127829.
From Johannes W. Meijer, Jun 05 2011: (Start)
The Ze3 and Ze4 triangle sums, see A180662 for their definitions, of Sierpinski's triangle A047999 equal this sequence.
The sequences A127830(2^n-p), p>=0, are apparently all Fibonacci like sequences, i.e., the next term is the sum of the two nonzero terms that precede it; see the crossrefs. (End)

Crossrefs

Cf.: A000045 (p=0), A000204 (p=7), A001060 (p=13), A000285 (p=14), A022095 (p=16), A022120 (p=24), A022121 (p=25), A022113 (p=28), A022096 (p=30), A022097 (p=31), A022098 (p=32), A022130 (p=44), A022137 (p=48), A022138 (p=49), A022122 (p=52), A022114 (p=53), A022123 (p=56), A022115 (p=60), A022100 (p=62), A022101 (p=63), A022103 (p=64), A022136 (p=79), A022388 (p=80), A022389 (p=88). - Johannes W. Meijer, Jun 05 2011

Programs

  • Maple
    A127830 := proc(n) local k: option remember: add(binomial(floor(k/2), n-k) mod 2, k=0..n) end: seq(A127830(n), n=0..80); # Johannes W. Meijer, Jun 05 2011
  • Mathematica
    Table[Sum[Mod[Binomial[Floor[k/2],n-k],2],{k,0,n}],{n,0,80}] (* James C. McMahon, Jan 04 2025 *)
  • Python
    def A127830(n): return sum(not ~(k>>1)&n-k for k in range(n+1)) # Chai Wah Wu, Jul 29 2025

Formula

a(2^n) = F(n); a(2^(n+1)+1) = L(n).
a(n) mod 2 = A000931(n+5) mod 2 = A011656(n+4).

A353595 Array read by ascending antidiagonals. Generalized Fibonacci numbers F(n, k) = (psi^(k - 1)*(phi + n) - phi^(k - 1)*(psi + n)) / (psi - phi) where phi = (1+sqrt(5))/2 and psi = (1-sqrt(5))/2. F(n, k) for n >= 0 and k >= 0.

Original entry on oeis.org

0, 1, 1, 2, 1, 1, 3, 1, 2, 2, 4, 1, 3, 3, 3, 5, 1, 4, 4, 5, 5, 6, 1, 5, 5, 7, 8, 8, 7, 1, 6, 6, 9, 11, 13, 13, 8, 1, 7, 7, 11, 14, 18, 21, 21, 9, 1, 8, 8, 13, 17, 23, 29, 34, 34, 10, 1, 9, 9, 15, 20, 28, 37, 47, 55, 55, 11, 1, 10, 10, 17, 23, 33, 45, 60, 76, 89, 89
Offset: 0

Views

Author

Peter Luschny, May 09 2022

Keywords

Comments

The definition declares the Fibonacci numbers for all integers n and k. It gives the classical Fibonacci numbers as F(0, n) = A000045(n). A different enumeration is given in A352744.

Examples

			Array starts:
n\k 0, 1,  2,  3,  4,  5,  6,   7,   8,   9, ...
--------------------------------------------------------
[0]  0, 1,  1,  2,  3,  5,  8, 13,  21,  34, ... A000045
[1]  1, 1,  2,  3,  5,  8, 13, 21,  34,  55, ... A000045 (shifted once)
[2]  2, 1,  3,  4,  7, 11, 18, 29,  47,  76, ... A000032
[3]  3, 1,  4,  5,  9, 14, 23, 37,  60,  97, ... A104449
[4]  4, 1,  5,  6, 11, 17, 28, 45,  73, 118, ... [4] + A022095
[5]  5, 1,  6,  7, 13, 20, 33, 53,  86, 139, ... [5] + A022096
[6]  6, 1,  7,  8, 15, 23, 38, 61,  99, 160, ... [6] + A022097
[7]  7, 1,  8,  9, 17, 26, 43, 69, 112, 181, ... [7] + A022098
[8]  8, 1,  9, 10, 19, 29, 48, 77, 125, 202, ... [8] + A022099
[9]  9, 1, 10, 11, 21, 32, 53, 85, 138, 223, ... [9] + A022100
		

Crossrefs

Cf. A000045, A000032, A104449, A094588 (main diagonal).
Cf. A352744, A354265 (generalized Lucas numbers).

Programs

  • Julia
    function fibrec(n::Int)
        n == 0 && return (BigInt(0), BigInt(1))
        a, b = fibrec(div(n, 2))
        c = a * (b * 2 - a)
        d = a * a + b * b
        iseven(n) ? (c, d) : (d, c + d)
    end
    function Fibonacci(n::Int, k::Int)
        k == 0 && return BigInt(n)
        k == 1 && return BigInt(1)
        k  < 0 && return (-1)^(k-1)*Fibonacci(-n - 1, 2 - k)
        a, b = fibrec(k - 1)
        a*n + b
    end
    for n in -6:6
        println([n], [Fibonacci(n, k) for k in -6:6])
    end
  • Maple
    f := n -> combinat:-fibonacci(n): F := (n, k) -> n*f(k - 1) + f(k):
    seq(seq(F(n - k, k), k = 0..n), n = 0..11);
    # The next implementation is for illustration only but is not recommended
    # as it relies on floating point arithmetic. Illustrates the case n,k < 0.
    phi := (1 + sqrt(5))/2: psi := (1 - sqrt(5))/2:
    F := (n, k) -> (psi^(k-1)*(psi + n) - phi^(k-1)*(phi + n)) / (psi - phi):
    for n from -6 to 6 do lprint(seq(simplify(F(n, k)), k = -6..6)) od;
  • Mathematica
    (* Works also for n < 0 and k < 0. Uses a remark from Bill Gosper. *)
    c := I*ArcSinh[1/2] - Pi/2;
    F[n_, k_] := (n Sin[(k - 1) c] - I Sin[k c]) / (I^k Sqrt[5/4]);
    Table[Simplify[F[n, k]], {n, 0, 6}, {k, 0, 6}] // TableForm

Formula

Functional equation extends Cassini's theorem:
F(n, k) = (-1)^(k - 1)*F(-n - 1, 2 - k).
F(n, k) = ((1 - phi)^(k - 1)*(1 - phi + n) - phi^(k - 1)*(phi + n))/(1 - 2*phi).
F(n, k) = n*fib(k - 1) + fib(k), where fib(n) are the classical Fibonacci numbers A000045 extended in the usual way for negative n.
F(n, k) - F(n-1, k) = fib(k-1).
F(n, k) = F(n, k-1) + F(n, k-2).
F(n, k) = (n*sin((k - 1)*c) - i*sin(k*c))/(i^k*sqrt(5/4)) where c = i*arcsinh(1/2) - Pi/2, for all n, k in Z. Based on a remark of Bill Gosper.

A022372 Fibonacci sequence beginning 2, 20.

Original entry on oeis.org

2, 20, 22, 42, 64, 106, 170, 276, 446, 722, 1168, 1890, 3058, 4948, 8006, 12954, 20960, 33914, 54874, 88788, 143662, 232450, 376112, 608562, 984674, 1593236, 2577910, 4171146, 6749056, 10920202
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A022100.

Programs

  • Mathematica
    a={};b=2;c=20;AppendTo[a, b];AppendTo[a, c];Do[b=b+c;AppendTo[a, b];c=b+c;AppendTo[a, c], {n, 4!}];a (* Vladimir Joseph Stephan Orlovsky, Sep 18 2008 *)
    Table[2*(Fibonacci[n + 2] + 8*Fibonacci[n]), {n,0,50}] (* or *) LinearRecurrence[{1,1}, {2,20}, 50] (* G. C. Greubel, Aug 27 2017 *)
  • PARI
    for(n=0,50, print1(2*(fibonacci(n+2) + 8*fibonacci(n)), ", ")) \\ G. C. Greubel, Aug 27 2017

Formula

G.f.: (2+18*x)/(1-x-x^2). - Philippe Deléham, Nov 19 2008
a(n) = 2*(Fibonacci(n+2) + 8*Fibonacci(n)). - G. C. Greubel, Aug 27 2017
a(n) = 2*A022100(n). - Alois P. Heinz, Aug 27 2017

A022314 a(n) = a(n-1) + a(n-2) + 1, with a(0) = 0, a(1) = 9.

Original entry on oeis.org

0, 9, 10, 20, 31, 52, 84, 137, 222, 360, 583, 944, 1528, 2473, 4002, 6476, 10479, 16956, 27436, 44393, 71830, 116224, 188055, 304280, 492336, 796617, 1288954, 2085572, 3374527, 5460100, 8834628, 14294729, 23129358, 37424088, 60553447, 97977536, 158530984
Offset: 0

Views

Author

Keywords

Examples

			G.f. = 9*x + 10*x^2 + 20*x^3 + 31*x^4 + 52*x^5 + 84*x^6 + 137*x^7 + 222*x^8 + ...
		

Crossrefs

Cf. A022100.

Programs

  • Mathematica
    LinearRecurrence[{2, 0, -1}, {0, 9, 10}, 60] (* Vladimir Joseph Stephan Orlovsky, Feb 11 2012 *)
    a[ n_] := 9 Fibonacci[n] + Fibonacci[n + 1] - 1; (* Michael Somos, Nov 21 2016 *)
  • PARI
    concat(0, Vec(-x*(-9+8*x) / ( (x-1)*(x^2+x-1) ) + O(x^30))) \\ Michel Marcus, Nov 20 2016
    {a(n) = 9*fibonacci(n) + fibonacci(n+1) - 1}; /* Michael Somos, Nov 21 2016 */

Formula

a(n) = -1 + (1/2)*((1 + sqrt(5))/2)^n + (19/10)sqrt(5)*((1 + sqrt(5))/2)^n - (19/10)*sqrt(5)*((1 - sqrt(5))/2)^n + (1/2)*((1 - sqrt(5))/2)^n, obtained using PURRS. - Alexander R. Povolotsky, Apr 22 2008
From R. J. Mathar, Apr 07 2011: (Start)
G.f.: -x*(-9+8*x) / ( (x-1)*(x^2+x-1) ).
a(n) = A022100(n) - 1. (End)
a(n) = F(n+2) + 8*F(n) - 1, where A000045. - G. C. Greubel, Aug 25 2017

A180175 Diagonal sums of A164844.

Original entry on oeis.org

1, 10, 101, 1011, 10112, 101123, 1011235, 10112358, 101123593, 1011235951, 10112359544, 101123595495, 1011235955039, 10112359550534, 101123595505573, 1011235955056107, 10112359550561680, 101123595505617787, 1011235955056179467, 10112359550561797254
Offset: 1

Views

Author

Mark Dols, Aug 15 2010

Keywords

Comments

Sums are built along inclined lines through the triangle with (1,2)-steps in the (row,column) indices. - R. J. Mathar, Aug 19 2010

Examples

			From _R. J. Mathar_, Aug 19 2010: (Start)
One example is a(5), the sum of numbers in parentheses:
  1;
  1, 10;
  (1), 11, 100;
  1, 12, (111) ; 1000;;
  1, 13, 123 ; 1111, (10000); (End)
		

Crossrefs

Formula

From R. J. Mathar, Aug 19 2010: (Start)
G.f.: ( 1-x ) / ( (10*x-1)*(x^2+x-1) ).
a(n) = +11*a(n-1) -9*a(n-2) -10*a(n-3).
a(n) = (90*10^n -A022100(n))/89. (End)

Extensions

More terms from R. J. Mathar, Aug 19 2010
Showing 1-8 of 8 results.