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.

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A017899 Expansion of 1/(1 -x^5 -x^6 -x^7 - ...).

Original entry on oeis.org

1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 8, 11, 15, 20, 26, 34, 45, 60, 80, 106, 140, 185, 245, 325, 431, 571, 756, 1001, 1326, 1757, 2328, 3084, 4085, 5411, 7168, 9496, 12580, 16665, 22076, 29244, 38740, 51320, 67985, 90061, 119305, 158045, 209365, 277350
Offset: 0

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Author

Keywords

Comments

a(n) is the number of compositions of n into parts >=5. - Joerg Arndt, Jun 22 2011
a(n+5) equals the number of binary words such that 0 appears only in runs whose lengths are a multiple of 5. - Milan Janjic, Feb 17 2015
a(n-5) equals the number of circular arrangements of the first n positive integers such that adjacent terms have absolute difference 2 or 3. - Ethan Patrick White, Jun 24 2020

Crossrefs

For Lamé sequences of orders 1 through 9 see A000045, A000930, A017898-A017904.
Apart from initial terms, same as A003520.

Programs

  • Maple
    f := proc(r) local t1,i; t1 := []; for i from 1 to r do t1 := [op(t1),0]; od: for i from 1 to r+1 do t1 := [op(t1),1]; od: for i from 2*r+2 to 50 do t1 := [op(t1),t1[i-1]+t1[i-1-r]]; od: t1; end; # set r = order
    a:= n-> (Matrix(5, (i,j)-> if (i=j-1) then 1 elif j=1 then [1, 0$3, 1][i] else 0 fi)^n)[5,5]: seq(a(n), n=0..50); # Alois P. Heinz, Aug 04 2008
  • Mathematica
    CoefficientList[ Series[(1 - x)/(1 - x - x^5), {x, 0, 50}], x] (* Adi Dani, Jun 25 2011 *)
    LinearRecurrence[{1,0,0,0,1},{1,0,0,0,0},60] (* Harvey P. Dale, Jun 07 2015 *)
  • PARI
    Vec((1-x)/(1-x-x^5)+O(x^99)) \\ Charles R Greathouse IV, Jun 21 2011

Formula

G.f.: (1-x)/(1-x-x^5) = 1/(1-Sum_{k>=5} x^k).
For positive integers n and k such that k <= n <= 5*k, and 4 divides n-k, define c(n,k) = binomial(k,(n-k)/4), and c(n,k) = 0, otherwise. Then, for n>=1, a(n+5) = Sum_{k=1..n} c(n,k). - Milan Janjic, Dec 09 2011

A264878 T(n,k)=Number of (n+1)X(k+1) arrays of permutations of 0..(n+1)*(k+1)-1 with each element having directed index change 0,1 0,-1 -2,0 or 1,1.

Original entry on oeis.org

1, 0, 1, 1, 0, 1, 0, 1, 0, 2, 1, 1, 5, 0, 3, 0, 7, 4, 20, 0, 4, 1, 20, 65, 12, 56, 0, 5, 0, 49, 228, 572, 36, 137, 0, 6, 1, 175, 1101, 2348, 3613, 108, 295, 0, 8, 0, 323, 4832, 22152, 22400, 19372, 324, 709, 0, 11, 1, 1085, 18501, 129230, 356692, 207424, 103585, 972, 1983, 0
Offset: 1

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Author

R. H. Hardin, Nov 27 2015

Keywords

Comments

Table starts
..1.0....1....0........1..........0............1..............0
..1.0....1....1........7.........20...........49............175
..1.0....5....4.......65........228.........1101...........4832
..2.0...20...12......572.......2348........22152.........129230
..3.0...56...36.....3613......22400.......356692........3303808
..4.0..137..108....19372.....207424......4747695.......78535556
..5.0..295..324...103585....1946752.....68488297.....1924357508
..6.0..709..972...629654...18265856...1050281271....47123513432
..8.0.1983.2916..3930725..171168256..16268725036..1152731721920
.11.0.5280.8748.23940621.1602206720.247512489984.28078658475952

Examples

			Some solutions for n=4 k=4
..1..2..3..4.14...10..2.12..4.14....1..2.12..4.14...10..2..3..4.14
.15..0..8..9.19....6..0..1..9..3...15..0..8..9..3....6..0..1..9.19
.20..5..6..7.24...20..5.22..7..8...20..5..6..7.24...20..5.22..7..8
.16.10.11.12.13...16.17.11.19.13...16.10.11.19.13...16.17.11.12.13
.21.22.23.17.18...21.15.23.24.18...21.22.23.17.18...21.15.23.24.18
		

Crossrefs

Column 1 is A003520(n+1).
Column 4 is A003946(n-2).

Formula

Empirical for column k:
k=1: a(n) = a(n-1) +a(n-5)
k=2: a(n) = a(n-1)
k=3: [order 45]
k=4: a(n) = 3*a(n-1) for n>3
Empirical for row n:
n=1: a(n) = a(n-2)
n=2: [order 20]
n=3: [order 46]

A278657 Number A(n,k) of tilings of a k X n rectangle using pentominoes of any shape and monominoes; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 7, 1, 1, 1, 2, 25, 50, 25, 2, 1, 1, 3, 50, 311, 311, 50, 3, 1, 1, 4, 155, 1954, 4101, 1954, 155, 4, 1, 1, 5, 508, 11914, 56864, 56864, 11914, 508, 5, 1, 1, 6, 1343, 76003, 728857, 1532496, 728857, 76003, 1343, 6, 1
Offset: 0

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Author

Alois P. Heinz, Nov 25 2016

Keywords

Examples

			A(2,3) = A(3,2) = 7:
  .___.  .___.  .___.  .___.  .___.  .___.  .___.
  |_|_|  |   |  |   |  | |_|  |_| |  | ._|  |_. |
  |_|_|  | ._|  |_. |  |   |  |   |  | |_|  |_| |
  |_|_|  |_|_|  |_|_|  |___|  |___|  |___|  |___| .
.
Square array A(n,k) begins:
  1, 1,   1,     1,      1,        1,          1, ...
  1, 1,   1,     1,      1,        2,          3, ...
  1, 1,   1,     7,     25,       50,        155, ...
  1, 1,   7,    50,    311,     1954,      11914, ...
  1, 1,  25,   311,   4101,    56864,     728857, ...
  1, 2,  50,  1954,  56864,  1532496,   42238426, ...
  1, 3, 155, 11914, 728857, 42238426, 2492016728, ...
		

Crossrefs

Columns (or rows) k=0-7 give: A000012, A003520, A278874, A278875, A278876, A278456, A278877, A278878.

A014097 a(n) = a(n-1)+a(n-4).

Original entry on oeis.org

1, 1, 1, 5, 6, 7, 8, 13, 19, 26, 34, 47, 66, 92, 126, 173, 239, 331, 457, 630, 869, 1200, 1657, 2287, 3156, 4356, 6013, 8300, 11456, 15812, 21825, 30125, 41581, 57393, 79218, 109343, 150924, 208317, 287535
Offset: 1

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Author

Keywords

Comments

Number of ways to cover (without overlapping) a ring lattice (necklace) of n sites with molecules that are 4 sites wide.
This comment covers a family of sequences which satisfy a recurrence of the form a(n) = a(n-1) + a(n-m), with a(n) = 1 for n = 1...m-1, a(m) = m+1. The generating function is (x+m*x^m)/(1-x-x^m). Also a(n) = 1 + n*Sum_{i=1..n/m} binomial(n-1-(m-1)*i, i-1)/i. This gives the number of ways to cover (without overlapping) a ring lattice (or necklace) of n sites with molecules that are m sites wide. Special cases: m=2: A000204, m=3: A001609, m=4: A014097, m=5: A058368, m=6: A058367, m=7: A058366, m=8: A058365, m=9: A058364.

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{1,0,0,1},{1,1,1,5},40] (* Harvey P. Dale, Mar 06 2016 *)
  • Maxima
    a(n):=sum(binomial(n-3*j,n-4*j)*n/(n-3*j),j,0,(n-1)/3); /* Vladimir Kruchinin, Mar 25 2016 */
    
  • PARI
    a(n)=([0,1,0,0; 0,0,1,0; 0,0,0,1; 1,0,0,1]^(n-1)*[1;1;1;5])[1,1] \\ Charles R Greathouse IV, Sep 09 2016

Formula

G.f.: -x*(1+4*x^3)/(-1+x+x^4). a(n)= 4*A003269(n)-3*A003269(n-1). - R. J. Mathar, Nov 16 2007
a(n) = Sum_{j=0..(n-1)/3}(binomial(n-3*j,n-4*j)*n/(n-3*j)). - Vladimir Kruchinin, Mar 25 2016
From Greg Dresden, Aug 23 2019: (Start)
a(n) = r1^n + r2^n + r3^n + r4^n, where {r1,r2,r3,r4} are the four roots of x^4-x^3-1=0, see A086106, A230151.
a(n) = round(r^n) for n>21 and r the positive real root of x^4-x^3-1.
(End)

Extensions

Additional comments from Yong Kong (ykong(AT)curagen.com), Dec 16 2000

A079675 a(1)=1; a(n)=sum(u=1,n-1,sum(v=1,u,sum(w=1,v,sum(x=1, w,sum(y=1,x,a(y)))))).

Original entry on oeis.org

1, 1, 6, 26, 106, 431, 1757, 7168, 29244, 119305, 486716, 1985603, 8100456, 33046585, 134816705, 549997641, 2243767969, 9153665985, 37343255690, 152345382480, 621507555626, 2535499503900, 10343812679475, 42198572937400
Offset: 1

Views

Author

Benoit Cloitre, Jan 26 2003

Keywords

Comments

Row sums of Riordan array (1,1/(1-x)^5). A quintisection of A003520. - Paul Barry, Feb 02 2006

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{6,-10,10,-5,1},{1,1,6,26,106,431},40] (* Harvey P. Dale, Aug 21 2017 *)

Formula

a(1)=1, a(2)=1, a(3)=6, a(4)=26, a(5)=106, a(6)=431; for n>=7, a(n)=5*u(n-1)-4*u(n-2)+u(n-3)+b(n) where b(n) is the 6 periodic sequence (0, 1, 1, 0, -1, -1)
G.f.: (1-x)^5/((1-x)^5-x); a(n)=sum{k=0..n, binomial(5n-4k-1,k)}; - Paul Barry, Feb 02 2006

A058368 Number of ways to cover (without overlapping) a ring lattice (necklace) of n sites with molecules that are 5 sites wide.

Original entry on oeis.org

1, 1, 1, 1, 6, 7, 8, 9, 10, 16, 23, 31, 40, 50, 66, 89, 120, 160, 210, 276, 365, 485, 645, 855, 1131, 1496, 1981, 2626, 3481, 4612, 6108, 8089, 10715, 14196, 18808, 24916, 33005, 43720, 57916, 76724, 101640, 134645, 178365, 236281, 313005, 414645
Offset: 1

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Author

Yong Kong (ykong(AT)curagen.com), Dec 17 2000

Keywords

Comments

This comment covers a family of sequences which satisfy a recurrence of the form a(n) = a(n-1) + a(n-m), with a(n) = 1 for n = 1...m-1, a(m) = m+1. The generating function is (x+m*x^m)/(1-x-x^m). Also a(n) = 1 + n*Sum_{i=1..n/m} binomial(n-1-(m-1)*i, i-1)/i. This gives the number of ways to cover (without overlapping) a ring lattice (or necklace) of n sites with molecules that are m sites wide. Special cases: m=2: A000204, m=3: A001609, m=4: A014097, m=5: A058368, m=6: A058367, m=7: A058366, m=8: A058365, m=9: A058364.

Examples

			a(5) = 6 because there is one way to put zero molecule to the necklace and 5 ways to put one molecule.
		

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{1,0,0,0,1},{1,1,1,1,6},50] (* Harvey P. Dale, Aug 14 2020 *)

Formula

a(n) = 1 + n*Sum_{i=1..n/5} binomial(n-4*i-1, i-1)/i.
a(n) = a(n-1) + a(n-5) for n >= 6.
G.f.: (x+5*x^5)/(1-x-x^5).

A058364 Number of ways to cover (without overlapping) a ring lattice (necklace) of n sites with molecules that are 9 sites wide.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 28, 39, 51, 64, 78, 93, 109, 126, 144, 172, 211, 262, 326, 404, 497, 606, 732, 876, 1048, 1259, 1521, 1847, 2251, 2748, 3354, 4086, 4962, 6010, 7269, 8790, 10637, 12888, 15636, 18990, 23076, 28038
Offset: 1

Views

Author

Yong Kong (ykong(AT)curagen.com), Dec 17 2000

Keywords

Comments

This comment covers a family of sequences which satisfy a recurrence of the form a(n) = a(n-1) + a(n-m), with a(n) = 1 for n = 1...m-1, a(m) = m+1. The generating function is (x+m*x^m)/(1-x-x^m). Also a(n) = 1 + n*Sum_{i=1..n/m} binomial(n-1-(m-1)*i, i-1)/i. This gives the number of ways to cover (without overlapping) a ring lattice (or necklace) of n sites with molecules that are m sites wide. Special cases: m=2: A000204, m=3: A001609, m=4: A014097, m=5: A058368, m=6: A058367, m=7: A058366, m=8: A058365, m=9: A058364.

Examples

			a(9) = 10 because there is one way to put zero molecule to the necklace and 9 ways to put one molecule.
		

References

  • E. Di Cera and Y. Kong, Theory of multivalent binding in one and two-dimensional lattices, Biophysical Chemistry, Vol. 61 (1996), pp. 107-124.
  • Y. Kong, General recurrence theory of ligand binding on a three-dimensional lattice, J. Chem. Phys. Vol. 111 (1999), pp. 4790-4799.

Crossrefs

Formula

a(n) = 1 + n*sum(binomial(n-1-8*i, i-1)/i, i=1..n/9). a(n) = a(n-1) + a(n-9), a(n) = 1 for n = 1..8, a(9) = 10. generating function = (x+9*x^9)/(1-x-x^9).

A058365 Number of ways to cover (without overlapping) a ring lattice (necklace) of n sites with molecules that are 8 sites wide.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 9, 10, 11, 12, 13, 14, 15, 16, 25, 35, 46, 58, 71, 85, 100, 116, 141, 176, 222, 280, 351, 436, 536, 652, 793, 969, 1191, 1471, 1822, 2258, 2794, 3446, 4239, 5208, 6399, 7870, 9692, 11950, 14744, 18190, 22429, 27637, 34036, 41906
Offset: 1

Views

Author

Yong Kong (ykong(AT)curagen.com), Dec 17 2000

Keywords

Comments

This comment covers a family of sequences which satisfy a recurrence of the form a(n) = a(n-1) + a(n-m), with a(n) = 1 for n = 1...m-1, a(m) = m+1. The generating function is (x+m*x^m)/(1-x-x^m). Also a(n) = 1 + n*Sum_{i=1..n/m} binomial(n-1-(m-1)*i, i-1)/i. This gives the number of ways to cover (without overlapping) a ring lattice (or necklace) of n sites with molecules that are m sites wide. Special cases: m=2: A000204, m=3: A001609, m=4: A014097, m=5: A058368, m=6: A058367, m=7: A058366, m=8: A058365, m=9: A058364.

Examples

			a(8) = 9 because there is one way to put zero molecule to the necklace and 8 ways to put one molecule.
		

References

  • E. Di Cera and Y. Kong, Theory of multivalent binding in one and two-dimensional lattices, Biophysical Chemistry, Vol. 61 (1996), pp. 107-124.
  • Y. Kong, General recurrence theory of ligand binding on a three-dimensional lattice, J. Chem. Phys. Vol. 111 (1999), pp. 4790-4799.

Crossrefs

Formula

a(n) = 1 + n*sum(binomial(n-1-7*i, i-1)/i, i=1..n/8). a(n) = a(n-1) + a(n-8), a(n) = 1 for n = 1..7, a(8) = 9. generating function = (x+8*x^8)/(1-x-x^8).

A058366 Number of ways to cover (without overlapping) a ring lattice (necklace) of n sites with molecules that are 7 sites wide.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 8, 9, 10, 11, 12, 13, 14, 22, 31, 41, 52, 64, 77, 91, 113, 144, 185, 237, 301, 378, 469, 582, 726, 911, 1148, 1449, 1827, 2296, 2878, 3604, 4515, 5663, 7112, 8939, 11235, 14113, 17717, 22232, 27895, 35007, 43946, 55181, 69294, 87011
Offset: 1

Views

Author

Yong Kong (ykong(AT)curagen.com), Dec 17 2000

Keywords

Comments

This comment covers a family of sequences which satisfy a recurrence of the form a(n) = a(n-1) + a(n-m), with a(n) = 1 for n = 1...m-1, a(m) = m+1. The generating function is (x+m*x^m)/(1-x-x^m). Also a(n) = 1 + n*Sum_{i=1..n/m} binomial(n-1-(m-1)*i, i-1)/i. This gives the number of ways to cover (without overlapping) a ring lattice (or necklace) of n sites with molecules that are m sites wide. Special cases: m=2: A000204, m=3: A001609, m=4: A014097, m=5: A058368, m=6: A058367, m=7: A058366, m=8: A058365, m=9: A058364.

Examples

			a(7) = 8 because there is one way to put zero molecule to the necklace and 7 ways to put one molecule.
		

References

  • E. Di Cera and Y. Kong, Theory of multivalent binding in one and two-dimensional lattices, Biophysical Chemistry, Vol. 61 (1996), pp. 107-124.
  • Y. Kong, General recurrence theory of ligand binding on a three-dimensional lattice, J. Chem. Phys. Vol. 111 (1999), pp. 4790-4799.

Crossrefs

Formula

a(n) = 1 + n*sum(binomial(n-1-6*i, i-1)/i, i=1..n/7). a(n) = a(n-1) + a(n-7), a(n) = 1 for n = 1..6, a(7) = 8. generating function = (x+7*x^7)/(1-x-x^7).

A058367 Number of ways to cover (without overlapping) a ring lattice (necklace) of n sites with molecules that are 6 sites wide.

Original entry on oeis.org

1, 1, 1, 1, 1, 7, 8, 9, 10, 11, 12, 19, 27, 36, 46, 57, 69, 88, 115, 151, 197, 254, 323, 411, 526, 677, 874, 1128, 1451, 1862, 2388, 3065, 3939, 5067, 6518, 8380, 10768, 13833, 17772, 22839, 29357, 37737, 48505, 62338, 80110, 102949, 132306, 170043, 218548
Offset: 1

Views

Author

Yong Kong (ykong(AT)curagen.com), Dec 17 2000

Keywords

Comments

This comment covers a family of sequences which satisfy a recurrence of the form a(n) = a(n-1) + a(n-m), with a(n) = 1 for n = 1...m-1, a(m) = m+1. The generating function is (x+m*x^m)/(1-x-x^m). Also a(n) = 1 + n*Sum_{i=1..n/m} binomial(n-1-(m-1)*i, i-1)/i. This gives the number of ways to cover (without overlapping) a ring lattice (or necklace) of n sites with molecules that are m sites wide. Special cases: m=2: A000204, m=3: A001609, m=4: A014097, m=5: A058368, m=6: A058367, m=7: A058366, m=8: A058365, m=9: A058364.

Examples

			a(6) = 7 because there is one way to put zero molecule to the necklace and 6 ways to put one molecule.
		

References

  • E. Di Cera and Y. Kong, Theory of multivalent binding in one and two-dimensional lattices, Biophysical Chemistry, Vol. 61 (1996), pp. 107-124.
  • Y. Kong, General recurrence theory of ligand binding on a three-dimensional lattice, J. Chem. Phys. Vol. 111 (1999), pp. 4790-4799.

Crossrefs

Formula

a(n) = 1 + n*sum(binomial(n-1-5*i, i-1)/i, i=1..n/6). a(n) = a(n-1) + a(n-6), a(n) = 1 for n = 1..5, a(6) = 7. generating function = (x+6*x^6)/(1-x-x^6).
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