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.

Previous Showing 11-18 of 18 results.

A018910 Pisot sequence L(4,5).

Original entry on oeis.org

4, 5, 7, 10, 15, 23, 36, 57, 91, 146, 235, 379, 612, 989, 1599, 2586, 4183, 6767, 10948, 17713, 28659, 46370, 75027, 121395, 196420, 317813, 514231, 832042, 1346271, 2178311, 3524580, 5702889, 9227467, 14930354, 24157819, 39088171, 63245988, 102334157, 165580143
Offset: 0

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Author

Keywords

Crossrefs

See A008776 for definitions of Pisot sequences.

Programs

  • Mathematica
    LinearRecurrence[{2, 0, -1}, {4, 5, 7}, 40] (* Jean-François Alcover, Dec 12 2016 *)
  • PARI
    pisotL(nmax, a1, a2) = {
      a=vector(nmax); a[1]=a1; a[2]=a2;
      for(n=3, nmax, a[n] = ceil(a[n-1]^2/a[n-2]));
      a
    }
    pisotL(50, 4, 5) \\ Colin Barker, Aug 07 2016

Formula

a(n) = Fib(n+3)+2 = A020743(n-2) = A157725(n+3); a(n) = 2a(n-1) - a(n-3).
G.f.: -(-4+3*x+3*x^2)/(x-1)/(x^2+x-1) = -2/(x-1)+(-x-2)/(x^2+x-1) . - R. J. Mathar, Nov 23 2007

A214781 a(n) = smallest k>=2 such that n divides Fibonacci(k-1)+2.

Original entry on oeis.org

2, 4, 2, 4, 5, 10, 6, 0, 10, 7, 0, 10, 12, 22, 8, 0, 16, 10, 11, 28, 0, 0, 9, 0, 48, 40, 34, 22, 0, 34, 0, 0, 0, 16, 28, 10, 36, 0, 18, 0, 18, 0, 17, 0, 34, 22, 14, 0, 54, 148, 16, 40, 52, 34, 0, 0, 11, 0, 0, 34, 28, 0, 0, 0, 68, 0, 21, 16
Offset: 1

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Author

Art DuPre, Aug 03 2012

Keywords

Comments

0 is inserted if no such k exists.

Examples

			n=1 divides F(0)+2=2. n=2 divides F(0)+2=2. n=3 divides F(1)+2=3. n=4 divides F(3)+2=4.
		

Crossrefs

Programs

  • PARI
    a(n) = {k = 2; while (((fibonacci(k-1)+2) % n), k++; if (k > 6*n+2 , return(0));); return (k);} \\ Michel Marcus, May 30 2013

A298187 T(n,k)=Number of nXk 0..1 arrays with every element equal to 3, 5, 7 or 8 king-move adjacent elements, with upper left element zero.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 2, 1, 2, 0, 0, 3, 2, 2, 3, 0, 0, 5, 3, 3, 3, 5, 0, 0, 8, 5, 4, 4, 5, 8, 0, 0, 13, 8, 6, 5, 6, 8, 13, 0, 0, 21, 13, 9, 7, 7, 9, 13, 21, 0, 0, 34, 21, 14, 10, 10, 10, 14, 21, 34, 0, 0, 55, 34, 22, 15, 14, 14, 15, 22, 34, 55, 0, 0, 89, 55, 35, 23, 20, 19, 20, 23, 35, 55
Offset: 1

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Author

R. H. Hardin, Jan 14 2018

Keywords

Comments

Table starts
.0..0..0..0..0..0..0..0..0...0...0...0...0....0....0....0....0.....0.....0
.0..1..1..2..3..5..8.13.21..34..55..89.144..233..377..610..987..1597..2584
.0..1..1..2..3..5..8.13.21..34..55..89.144..233..377..610..987..1597..2584
.0..2..2..3..4..6..9.14.22..35..56..90.145..234..378..611..988..1598..2585
.0..3..3..4..5..7.10.15.23..36..57..91.146..235..379..612..989..1599..2586
.0..5..5..6..7.10.14.20.29..44..68.106.166..262..416..663.1059..1695..2718
.0..8..8..9.10.14.19.27.38..58..90.142.225..362..587..959.1572..2587..4270
.0.13.13.14.15.20.27.41.58..91.145.240.398..680.1157.2003.3476..6073.10620
.0.21.21.22.23.29.38.58.81.127.203.341.574.1019.1784.3212.5779.10480.18971

Examples

			Some solutions for n=7 k=4
..0..0..0..0. .0..0..1..1. .0..0..0..0. .0..0..0..0. .0..0..0..0
..0..0..0..0. .0..0..1..1. .0..0..0..0. .0..0..0..0. .0..0..0..0
..0..0..0..0. .0..0..1..1. .0..0..0..0. .1..1..1..1. .0..0..0..0
..0..0..0..0. .0..0..1..1. .1..1..1..1. .1..1..1..1. .1..1..1..1
..0..0..0..0. .0..0..1..1. .1..1..1..1. .1..1..1..1. .1..1..1..1
..0..0..0..0. .0..0..1..1. .1..1..1..1. .0..0..0..0. .0..0..0..0
..0..0..0..0. .0..0..1..1. .1..1..1..1. .0..0..0..0. .0..0..0..0
		

Crossrefs

Column 2 is A000045(n-1).
Column 3 is A000045(n-1).
Column 4 is A001611(n-1).
Column 5 is A157725(n-1).

Formula

Empirical for column k:
k=1: a(n) = a(n-1)
k=2: a(n) = a(n-1) +a(n-2)
k=3: a(n) = a(n-1) +a(n-2)
k=4: a(n) = 2*a(n-1) -a(n-3) for n>4
k=5: a(n) = 2*a(n-1) -a(n-3) for n>4
k=6: a(n) = 3*a(n-1) -2*a(n-2) -a(n-3) +2*a(n-4) -2*a(n-5) +a(n-7) for n>8
k=7: a(n) = 3*a(n-1) -2*a(n-2) -a(n-3) +2*a(n-4) -2*a(n-5) +a(n-6) -a(n-7) +a(n-8) -a(n-10) +a(n-11) for n>12

A020743 Pisot sequence L(7,10).

Original entry on oeis.org

7, 10, 15, 23, 36, 57, 91, 146, 235, 379, 612, 989, 1599, 2586, 4183, 6767, 10948, 17713, 28659, 46370, 75027, 121395, 196420, 317813, 514231, 832042, 1346271, 2178311, 3524580, 5702889, 9227467, 14930354, 24157819, 39088171, 63245988, 102334157, 165580143
Offset: 0

Views

Author

Keywords

Crossrefs

Subsequence of A018910. See A008776 for definitions of Pisot sequences.
Cf. A020717.

Programs

  • Mathematica
    LinearRecurrence[{2,0,-1},{7,10,15},40] (* Harvey P. Dale, Jun 10 2022 *)
  • PARI
    pisotL(nmax, a1, a2) = {
      a=vector(nmax); a[1]=a1; a[2]=a2;
      for(n=3, nmax, a[n] = ceil(a[n-1]^2/a[n-2]));
      a
    }
    pisotL(50, 7, 10) \\ Colin Barker, Aug 07 2016

Formula

a(n) = Fib(n+5)+2 = A157725(n+5). a(n) = 2a(n-1) - a(n-3).

A158569 a(n) = Sum_{i=1..F(n)} F(i), where F = A000045, Fibonacci numbers.

Original entry on oeis.org

0, 1, 1, 2, 4, 12, 54, 609, 28656, 14930351, 365435296161, 4660046610375530308, 1454489111232772683678306641952, 5789092068864820527338372482892113982249794889764, 7191684930184179482016276395611672639105248126232175323349533708710427892956420
Offset: 0

Views

Author

Ctibor O. Zizka, Mar 21 2009

Keywords

Comments

a(14) has 79 digits. - Emeric Deutsch, Apr 05 2009

Crossrefs

Programs

  • Maple
    with(combinat): a := proc (n) options operator, arrow: add(fibonacci(i), i = 1 .. fibonacci(n)) end proc: seq(a(n), n = 0 .. 14); # Emeric Deutsch, Apr 05 2009
    # second Maple program:
    F:= n-> (<<0|1>, <1|1>>^n)[1, 2]:
    a:= n-> F(F(n)+2)-1:
    seq(a(n), n=0..14);  # Alois P. Heinz, Apr 14 2025
  • Mathematica
    Total/@Table[Sum[Fibonacci[Range[i]],{i,{Fibonacci[n]}}],{n,14}] (* Harvey P. Dale, Aug 26 2013 *)

Formula

a(n) = A000071(A157725(n)). - Alois P. Heinz, Apr 14 2025

Extensions

More terms from Emeric Deutsch, Apr 05 2009

A226649 Fibonacci shuffles: a(2n) = A000071(n) and a(2n+1) = A001611(n+2).

Original entry on oeis.org

0, 2, 0, 3, 1, 4, 2, 6, 4, 9, 7, 14, 12, 22, 20, 35, 33, 56, 54, 90, 88, 145, 143, 234, 232, 378, 376, 611, 609, 988, 986, 1598, 1596, 2585, 2583, 4182, 4180, 6766, 6764, 10947, 10945, 17712, 17710, 28658, 28656, 46369, 46367, 75026, 75024, 121394, 121392, 196419, 196417, 317812, 317810
Offset: 0

Views

Author

V. T. Jayabalaji, Jun 14 2013

Keywords

Comments

a(2*n+1) = a(2*n) + A157725(n); a(2*n) = a(2*n-1) - 2 for n > 0. - Reinhard Zumkeller, Jul 30 2013

Crossrefs

Programs

  • Haskell
    import Data.List (transpose)
    a226649 n = a226649_list !! n
    a226649_list = concat $ transpose [a000071_list, drop 2 a001611_list]
    -- Reinhard Zumkeller, Jul 30 2013
  • Mathematica
    LinearRecurrence[{-1,1,1,1,1},{0,2,0,3,1},60] (* Harvey P. Dale, Sep 12 2018 *)

Formula

G.f. -x*(2+x^2+2*x^3+2*x) / ( (1+x)*(x^4+x^2-1) ). - R. J. Mathar, Jul 15 2013
a(n) + a(n+1) = A096748(n+2). - R. J. Mathar, Jul 15 2013
a(2n-1) - 1 = a(2n) + 1 = fib(n+1) = A000045(n+1) for n > 0. - T. D. Noe, Jul 23 2013

A364005 Numbers whose Wythoff representation (A189921, A317208) is palindromic.

Original entry on oeis.org

0, 1, 2, 5, 7, 10, 13, 15, 23, 28, 34, 36, 52, 57, 65, 75, 81, 89, 91, 117, 128, 146, 159, 175, 185, 198, 204, 217, 233, 235, 277, 295, 327, 369, 379, 400, 426, 442, 463, 473, 494, 520, 526, 547, 573, 589, 610, 612, 680, 709, 761, 829, 848, 916, 945, 989, 1023
Offset: 1

Views

Author

Amiram Eldar, Jul 01 2023

Keywords

Comments

Includes all the odd-indexed Fibonacci numbers (A001519), since the Wythoff representation of Fibonacci(1) is 1 and the Wythoff representation of Fibonacci(2*n+1), for n >= 1, is n 0's.
A157725(n) = Fibonacci(n) + 2 is a term for n >= 4, since its Wythoff representation is n-4 1's between 2 0's.
A232970 is a subsequence since the Wythoff representation of A232970(n) = (Fibonacci(3*n+1) + 1)/2 is n 0's and n-1 1's interleaved.

Examples

			The first 10 terms are:
   n  a(n)  A317208(a(n))
  --  ----  -------------
   1     0              0
   2     1              1
   3     2              2
   4     5             22
   5     7            212
   6    10           2112
   7    13            222
   8    15          21112
   9    23         211112
  10    28          21212
		

Crossrefs

Programs

  • Mathematica
    z[n_] := Floor[(n + 1)*GoldenRatio] - n - 1; h[n_] := z[n] - z[n - 1]; w[n_] := Module[{m = n, zm = 0, hm, s = {}}, While[zm != 1, hm = h[m]; AppendTo[s, hm]; If[hm == 1, zm = z[m], zm = z[z[m]]]; m = zm]; s]; w[0] = {0}; Select[Range[0, 1000], PalindromeQ[w[#]] &]

A217762 Square array T, read by antidiagonals: T(n,k) = F(n) + 2*F(k) where F(n) is the n-th Fibonacci number.

Original entry on oeis.org

0, 2, 1, 2, 3, 1, 4, 3, 3, 2, 6, 5, 3, 4, 3, 10, 7, 5, 4, 5, 5, 16, 11, 7, 6, 5, 7, 8, 26, 17, 11, 8, 7, 7, 10, 13, 42, 27, 17, 12, 9, 9, 10, 15, 21, 68, 43, 27, 18, 13, 11, 12, 15, 23, 34, 110, 69, 43, 28, 19, 15, 14, 17, 23, 36, 55, 178, 111, 69, 44, 29, 21
Offset: 0

Views

Author

Philippe Deléham, Apr 07 2013

Keywords

Examples

			Square array begins:
...0....2....2....4....6...10...16...26...42...
...1....3....3....5....7...11...17...27...43...
...1....3....3....5....7...11...17...27...43...
...2....4....4....6....8...12...18...28...44...
...3....5....5....7....9...13...19...29...45...
...5....7....7....9...11...15...21...31...47...
...8...10...10...12...14...18...24...34...50...
..13...15...15...17...19...23...29...39...55...
..21...23...23...25...27...31...37...47...63...
..34...36...36...38...40...44...50...60...76...
..55...57...57...59...61...65...71...81...97...
..89...91...91...93...95...99..105..115..131...
.144..146..146..148..150..154..160..170..186...
...
		

Crossrefs

Formula

T(n,0) = A000045(n).
T(1,k) = A001588(k).
T(n,1) = T(n,2) = A157725(n).
T(n,3) = A157727(n).
T(n,n)= A022086(n) = 3*A000045(n).
T(n+1,n) = A000032(n+1) = A000204(n+1).
T(n+2,n) = A000285(n).
T(n+3,n) = A013655(n+1) = A001060(n+1).
T(n+4,n) = A021120(n).
T(n+5,n) = A022088(n+2) = 5*A000045(n+2).
T(n+6,n) = A022097(n+2).
T(n+7,n) = A022122(n+2).
T(n+8,n) = 3*A013655(n+2).
T(n+9,n) = A097657(n+2).
T(n+10,n) = A022118(n+4).
T(n,n+1) = A000045(n+3).
T(n,n+2) = A013655(n+1) = A001060(n+1).
T(n,n+3) = A000032(n+3).
T(n,n+4) = A022095(n+2).
T(n,n+5) = A022120(n+2).
T(n,n+6) = A022136(n+2).
T(n,n+7) = A022098(n+4).
T(n,n+8) = A022380(n+4).
T(n,n+9) = A206419(n+6).
Sum(T(n-k,k), 0<=k<=n) = 3*A000071(n+2).
Previous Showing 11-18 of 18 results.