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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A079921 Solution to the Dancing School Problem with n girls and n+2 boys: f(n,2).

Original entry on oeis.org

3, 7, 14, 26, 46, 79, 133, 221, 364, 596, 972, 1581, 2567, 4163, 6746, 10926, 17690, 28635, 46345, 75001, 121368, 196392, 317784, 514201, 832011, 1346239, 2178278, 3524546, 5702854, 9227431, 14930317, 24157781, 39088132, 63245948, 102334116, 165580101
Offset: 1

Views

Author

Jaap Spies, Jan 28 2003

Keywords

Comments

f(g,h) = per(B), the permanent of the (0,1)-matrix B of size g X g+h with b(i,j)=1 if and only if i <= j <= i+h. See A079908 for more information.
With offset 4, number of 132-avoiding two-stack sortable permutations which contain exactly one subsequence of type 123.

Crossrefs

Cf. Essentially the same as A001924.

Programs

  • Maple
    with(genfunc): Fz := 1/((-1+z)^2 * (1-z-z^2)); seq(rgf_term(Fz,z,n), n=1..30);
  • Mathematica
    CoefficientList[Series[(-z^3 + z^2 + 2*z - 3)/((z - 1)^2 (z^2 + z - 1)), {z, 0, 100}], z] (* Vladimir Joseph Stephan Orlovsky, Jul 08 2011 *)
    LinearRecurrence[{3,-2,-1,1},{3,7,14,26},40] (* Harvey P. Dale, Oct 17 2022 *)

Formula

a(n) = a(n-1)+a(n-2)+n+1, a(1)=3, a(2)=7.
G.f.: 1/((1-x)^2*(1-x-x^2)).
F(n+5) - n - 4, F(n) = A000045(n).
a(n) = 3*a(n-1)-2*a(n-2)-a(n-3)+a(n-4). - Wesley Ivan Hurt, Dec 03 2021

Extensions

More terms from Jaap Spies, Dec 15 2006

A079922 Solution to the Dancing School Problem with n girls and n+3 boys: f(n,3).

Original entry on oeis.org

4, 13, 36, 90, 212, 478, 1044, 2227, 4664, 9627, 19640, 39684, 79544, 158364, 313464, 617365, 1210588, 2364713, 4603388, 8934142, 17291756, 33385018, 64311660, 123634471, 237233712, 454429239, 869095472, 1659708488
Offset: 1

Views

Author

Jaap Spies, Jan 28 2003

Keywords

Comments

f(g,h) = per(B), the permanent of the (0,1)-matrix B of size g X g+h with b(i,j)=1 if and only if i <= j <= i+h. See A079908 for more information.

Crossrefs

Formula

Empirical g.f.: -x*(x^7-4*x^4+2*x^3+3*x-4) / ((x-1)^2*(x^3+x^2+x-1)^2). - Colin Barker, Jan 04 2015

Extensions

More terms from Jaap Spies, Dec 15 2006

A079923 Solution to the Dancing School Problem with n girls and n+4 boys: f(n,4).

Original entry on oeis.org

5, 21, 76, 246, 738, 2108, 5794, 15458, 40296, 103129, 260019, 647617, 1596800, 3904260, 9479292, 22879520, 54947836, 131406732, 313129592, 743878505, 1762572329, 4167010597, 9832766588, 23164353834
Offset: 1

Views

Author

Jaap Spies, Jan 28 2003

Keywords

Comments

f(g,h) = per(B), the permanent of the (0,1)-matrix B of size g X g+h with b(i,j)=1 if and only if i <= j <= i+h. See A079908 for more information.

Crossrefs

Extensions

More terms from Jaap Spies, Dec 14 2006

A079924 Solution to the Dancing School Problem with n girls and n+5 boys: f(n,5).

Original entry on oeis.org

6, 31, 140, 566, 2104, 7364, 24720, 80196, 253072, 780902, 2365772, 7058469, 20789082, 60560175, 174763208, 500245052, 1421824896, 4016278792, 11283371280, 31547434008, 87827653936, 243578509132, 673221043496
Offset: 1

Views

Author

Jaap Spies, Jan 28 2003

Keywords

Comments

f(g,h) = per(B), the permanent of the (0,1)-matrix B of size g X g+h with b(i,j)=1 if and only if i <= j <= i+h. See A079908 for more information.

References

  • Jaap Spies, Dancing School Problems, Nieuw Archief voor Wiskunde 5/7 nr. 4, Dec 2006, pp. 283-285.

Crossrefs

Extensions

More terms from Jaap Spies, Dec 14 2006

A079925 Solution to the Dancing School Problem with n girls and n+6 boys: f(n,6).

Original entry on oeis.org

7, 43, 234, 1146, 5150, 21652, 86608, 334072, 1249768, 4557284, 16266830, 57031078, 196933710, 671224467, 2262089361, 7548882573, 24975936372, 82012110724, 267505920876, 867390073384
Offset: 1

Views

Author

Jaap Spies, Jan 28 2003

Keywords

Comments

f(g,h) = per(B), the permanent of the (0,1)-matrix B of size g X g+h with b(i,j)=1 if and only if i <= j <= i+h. See A079908 for more information.

Crossrefs

Extensions

Corrected by Jaap Spies, Feb 01 2004
More terms Dec 14 2006

A079927 Solution to the Dancing School Problem with n girls and n+8 boys: f(n,8).

Original entry on oeis.org

9, 73, 536, 3590, 22162, 127604, 693552, 3598120, 17990600, 87396728, 413977192, 1918222840, 8719846960, 38983643908, 171764779170, 747190081890, 3213760467348, 13684132415133, 57742830924831, 241687792906641
Offset: 1

Views

Author

Jaap Spies, Jan 28 2003

Keywords

Comments

f(g,h) = per(B), the permanent of the (0,1)-matrix B of size g X g+h with b(i,j)=1 if and only if i <= j <= i+h. See A079908 for more information.

Crossrefs

Extensions

Corrected by Jaap Spies, Feb 01 2004
More terms Dec 14 2006

A180276 Primes of the form n^3 + 3*n - 1.

Original entry on oeis.org

3, 13, 139, 233, 8059, 9323, 19763, 42979, 103963, 125149, 175783, 185363, 216179, 373463, 422099, 456763, 636313, 729269, 778963, 885023, 1061513, 1331329, 1367963, 1561243, 2000753, 2744419, 3724339, 4657963, 6435413, 6968443
Offset: 1

Views

Author

Graziano Aglietti (mg5055(AT)mclink.it), Aug 23 2010

Keywords

Comments

Subsequence of primes in the sequence defined as b(n) = n^3 + 3*n - 1 = 3, 13, 35, 75, 139, 233, 363, 535, ... = A079908(n) - 1.

Programs

  • Magma
    [ a: n in [0..250] | IsPrime(a) where a is (n^3+3*n-1)]; // Vincenzo Librandi, Jan 30 2011
  • Mathematica
    Select[Table[n^3+3n-1,{n,200}],PrimeQ] (* Harvey P. Dale, Sep 08 2024 *)
  • PARI
    a(n)=n^3+3*n-1;
    for(i=0,10^3,if(isprime(a(i)),print1(a(i), ", ")))
    

Extensions

Offset set to 1 by R. J. Mathar, Aug 25 2010

A180358 n^8+8n.

Original entry on oeis.org

0, 9, 272, 6585, 65568, 390665, 1679664, 5764857, 16777280, 43046793, 100000080, 214358969, 429981792, 815730825, 1475789168, 2562890745, 4294967424, 6975757577, 11019960720, 16983563193, 25600000160, 37822859529, 54875873712
Offset: 0

Views

Author

Odimar Fabeny, Aug 30 2010

Keywords

Crossrefs

Programs

  • Mathematica
    Table[n^8+8n,{n,0,30}] (* or *) LinearRecurrence[ {9,-36,84,-126,126,-84,36,-9,1},{0,9,272,6585,65568,390665,1679664,5764857,16777280},30] (* Harvey P. Dale, Jan 03 2012 *)

Formula

a(n)= +9*a(n-1) -36*a(n-2) +84*a(n-3) -126*a(n-4) +126*a(n-5) -84*a(n-6) +36*a(n-7) -9*a(n-8) +a(n-9). G.f.: x*(-9-191*x-4461*x^2-15339*x^3-15899*x^4-4125*x^5-303*x^6+7*x^7) / (x-1)^9 . [From R. J. Mathar, Sep 19 2010]

Extensions

a(0) corrected by R. J. Mathar, Sep 19 2010

A079916 Solution to the Dancing School Problem with 11 girls and n+11 boys: f(11,n).

Original entry on oeis.org

1, 12, 972, 19640, 260019, 2365772, 16266830, 89700624, 413977192, 1650607040, 5826331440, 18558391936, 54055214144, 145576033920, 365883104080, 865023114560, 1936764883296, 4130528893504, 8433028861040
Offset: 0

Views

Author

Jaap Spies, Jan 28 2003

Keywords

Comments

f(g,h) = per(B), the permanent of the (0,1)-matrix B of size g X g+h with b(i,j)=1 if and only if i <= j <= i+h. See A079908 for more information.
For fixed g, f(g,n) is polynomial in n for n >= g-2. See reference.

Crossrefs

Extensions

Corrected by Jaap Spies, Feb 01 2004

A079917 Solution to the Dancing School Problem with 12 girls and n+12 boys: f(12,n).

Original entry on oeis.org

1, 13, 1581, 39684, 647617, 7058469, 57031078, 363862092, 1918222840, 8641355080, 34132685120, 120629547584, 387665694976, 1145875468544, 3145428883520
Offset: 0

Views

Author

Jaap Spies, Jan 28 2003

Keywords

Comments

f(g,h) = per(B), the permanent of the (0,1)-matrix B of size g X g+h with b(i,j)=1 if and only if i <= j <= i+h. See A079908 for more information.
For fixed g, f(g,n) is polynomial in n for n >= g-2. See reference.

Crossrefs

Extensions

Corrected by Jaap Spies, Feb 01 2004
Previous Showing 21-30 of 35 results. Next