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 1-10 of 24 results. Next

A304082 a(n) = 3^n - A006952(n).

Original entry on oeis.org

0, 1, 1, 3, 3, 11, 9, 35, 33, 105, 105, 339, 313, 1035, 1017, 3115, 3099, 9579, 9345, 28947, 28713, 86979, 86825, 263187, 260865, 791577, 789497, 2376555, 2374521, 7150443, 7129401, 21471315, 21450489, 64431843, 64413177, 193487947, 193292811, 580650075
Offset: 0

Views

Author

Vaclav Kotesovec, May 06 2018

Keywords

Crossrefs

Cf. A006952, A264687.

Programs

  • Mathematica
    nmax = 60; 3^Range[0, nmax] - CoefficientList[Series[Product[(1 - x^k)/(1 - 3*x^k), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ 3^(n/2) / 2 if n is even and a(n) ~ 3^((n+1)/2) / 2 if n is odd.
a(n) ~ (1+sqrt(3) + (-1)^n*(1-sqrt(3))) * 3^(n/2) / 4.

A006951 Number of conjugacy classes in GL(n,2).

Original entry on oeis.org

1, 1, 3, 6, 14, 27, 60, 117, 246, 490, 1002, 1998, 4053, 8088, 16284, 32559, 65330, 130626, 261726, 523374, 1047690, 2095314, 4192479, 8384808, 16773552, 33546736, 67101273, 134202258, 268420086, 536839446, 1073710914, 2147420250, 4294904430, 8589807438
Offset: 0

Views

Author

N. J. A. Sloane

Keywords

Comments

Unlabeled permutations of sets. - Christian G. Bower, Jan 29 2004
From Joerg Arndt, Jan 02 2013: (Start)
Set q=2 and f(m)=q^(m-1)*(q-1), then a(n) is the sum over all partitions P of n over all products Product_{k=1..L} f(m_k) where L is the number of different parts in the partition P=[p_1^m_1, p_2^m_2, ..., p_L^m_L], see the Macdonald reference.
Setting q to a prime power gives the sequence "Number of conjugacy classes in GL(n,q)":
q=3: A006952, q=4: A049314, q=5: A049315, q=7: A049316, q=8: A182603,
q=9: A182604, q=11: A182605, q=13: A182606, q=16: A182607, q=17: A182608,
q=19: A182609, q=23: A182610, q=25: A182611, q=27: A182612.
Sequences where q is not a prime power are:
q=6: A221578, q=10: A221579, q=12: A221580,
q=14: A221581, q=15: A221582, q=18: A221583, q=20: A221584.
(End)
From Gus Wiseman, Jan 21 2019: (Start)
Also the number of ways to split an integer partition of n into consecutive constant subsequences. For example, the a(5) = 27 ways (subsequences shown as rows) are:
5 11111
.
4 3 3 22 2 1111 1 111 11
1 2 11 1 111 1 1111 11 111
.
3 2 2 2 111 1 1 11 11 1
1 2 11 1 1 111 1 11 1 11
1 1 1 11 1 1 111 1 11 11
.
2 11 1 1 1
1 1 11 1 1
1 1 1 11 1
1 1 1 1 11
.
1
1
1
1
1
(End)

Examples

			For the 5 partitions of 4 (namely [1^4]; [2,1^2]; [2^2]; [3,1]; [4]) we have
(f(m) = 2^(m-1)*(2-1) = 2^(m-1) and)
f([1^4]) = 2^3 = 8,
f([2,1^2]) = 1*2^1 = 2,
f([2^2]) = 2^1 = 2,
f([3,1]) = 1*1 = 1,
f([4]) = 1,
the sum is 8+2+2+1+1 = 14 = a(4).
- _Joerg Arndt_, Jan 02 2013

References

  • W. D. Smith, personal communication.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Crossrefs

Cf. A006952, A049314, A049315, A049316, A070933, A264685, A264687.
Column k=0 of A218698. - Alois P. Heinz, Nov 04 2012
Cf. A100471, A100883, A279784, A279786, A323433, A323582, A323583.

Programs

  • Magma
    /* The program does not work for n>19: */
[1] cat [NumberOfClasses(GL(n,2)): n in [1..19]]; // Sergei Haller (sergei(AT)sergei-haller.de), Dec 21 2006; edited by Vincenzo Librandi Jan 24 2013
  • Maple
    with(numtheory):
b:= n-> add(phi(d)*2^(n/d), d=divisors(n))/n-1:
a:= proc(n) option remember; `if`(n=0, 1,
       add(add(d*b(d), d=divisors(j)) *a(n-j), j=1..n)/n)
    end:
seq(a(n), n=0..40);  # Alois P. Heinz, Oct 20 2012
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*2^(n/d), {d, Divisors[n]}]/n-1; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*b[d], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 40}] (* Jean-François Alcover, Feb 17 2014, after Alois P. Heinz *)
Table[Sum[2^(Length[ptn]-Length[Split[ptn]]),{ptn,IntegerPartitions[n]}],{n,30}] (* Gus Wiseman, Jan 21 2019 *)
  • PARI
    N=66; x='x+O('x^N);
gf=prod(n=1,N, (1-x^n)/(1-2*x^n)  );
v=Vec(gf)
/* Joerg Arndt, Jan 02 2013 */

Formula

G.f.: Product_{n>=1} (1-x^n)/(1-2*x^n). - Joerg Arndt, Jan 02 2013
The number a(n) of conjugacy classes in the group GL(n, q) is the coefficient of t^n in Product_{k>=1} (1-t^k)/(1-q*t^k). - Noam Katz (noamkj(AT)hotmail.com), Mar 30 2001
Euler transform of A008965. - Christian G. Bower, Jan 29 2004
a(n) ~ 2^n - (1+sqrt(2) + (-1)^n*(1-sqrt(2))) * 2^(n/2-1). - Vaclav Kotesovec, Nov 21 2015
G.f.: exp(Sum_{k>=1} ( Sum_{d|k} d*(2^(k/d) - 1) ) * x^k/k). - Ilya Gutkovskiy, Sep 27 2018

Extensions

More terms from Christian G. Bower, Jan 29 2004

A049314 The number k(GL(n,q)) of conjugacy classes in GL(n,q), q=4.

Original entry on oeis.org

1, 3, 15, 60, 252, 1005, 4080, 16305, 65460, 261828, 1048260, 4192980, 16775955, 67103520, 268430160, 1073720415, 4294945932, 17179782540, 68719391100, 274877559420, 1099511281260, 4398045120300, 17592184654365, 70368738597600, 281474971147680
Offset: 0

Views

Author

Vladeta Jovovic

Keywords

Comments

Bound: k(GL(n,q))

References

  • Vladeta Jovovic, The cycle index polynomials of some classical groups, Belgrade, 1995, unpublished.

Links

Crossrefs

Cf. A006951, A006952, A049315, A049316.

Programs

  • Magma
    /* The program does not work for n>9: */ [1] cat [NumberOfClasses(GL(n,4)) : n in [1..8]]; // Sergei Haller (sergei(AT)sergei-haller.de), Dec 21 2006; edited by Vincenzo Librandi, Jan 23 2013
  • Maple
    with(numtheory):
b:= proc(n) b(n):= add(phi(d)*4^(n/d), d=divisors(n))/n-1 end:
a:= proc(n) a(n):= `if`(n=0, 1,
       add(add(d*b(d), d=divisors(j)) *a(n-j), j=1..n)/n)
    end:
seq(a(n), n=0..30);  # Alois P. Heinz, Nov 03 2012
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*4^(n/d), {d, Divisors[n]}]/n-1; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*b[d], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Jan 24 2014, after Alois P. Heinz *)
  • PARI
    x='x+O('x^30); Vec(prod(n=1, 30, (1-x^n)/(1-4*x^n))) \\ Altug Alkan, Sep 27 2018

Formula

The number a(n) of conjugacy classes in the group GL(n, q) is the coefficient of t^n in the infinite product: product k=1, 2, ... (1-t^k)/(1-qt^k) - Noam Katz (noamkj(AT)hotmail.com), Mar 30 2001.
G.f.: exp(Sum_{k>=1} ( Sum_{d|k} d*(4^(k/d) - 1) ) * x^k/k). - Ilya Gutkovskiy, Sep 27 2018

A049315 The number k(GL(n,q)) of conjugacy classes in GL(n,q), q=5.

Original entry on oeis.org

1, 4, 24, 120, 620, 3096, 15600, 77976, 390480, 1952380, 9764880, 48824280, 244136904, 1220683800, 6103496400, 30517481424, 152587794020, 762938966520, 3814696782120, 19073483892120, 95367429207720, 476837146020720, 2384185778835696, 11920928894086200
Offset: 0

Views

Author

Vladeta Jovovic

Keywords

References

  • V. Jovovic, The cycle index polynomials of some classical groups, Belgrade, 1995, unpublished.

Links

Crossrefs

Cf. A006951, A006952, A049314, A049316.

Programs

  • Magma
    /* The program does not work for n>8: */ [1] cat [NumberOfClasses(GL(n,5)) : n in [1..8]]; // Sergei Haller (sergei(AT)sergei-haller.de), Dec 21 2006; edited by Vincenzo Librandi, Jan 23 2013
  • Maple
    with(numtheory):
b:= proc(n) b(n):= add(phi(d)*5^(n/d), d=divisors(n))/n-1 end:
a:= proc(n) a(n):= `if`(n=0, 1,
       add(add(d*b(d), d=divisors(j)) *a(n-j), j=1..n)/n)
    end:
seq(a(n), n=0..30);  # Alois P. Heinz, Nov 03 2012
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*5^(n/d), {d, Divisors[n]}]/n-1; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*b[d], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Jan 24 2014, after Alois P. Heinz *)
  • PARI
    x='x+O('x^30); Vec(prod(n=1, 30, (1-x^n)/(1-5*x^n))) \\ Altug Alkan, Sep 27 2018

Formula

The number a(n) of conjugacy classes in the group GL(n, q) is the coefficient of t^n in the infinite product: product k=1, 2, ... (1-t^k)/(1-qt^k) - Noam Katz (noamkj(AT)hotmail.com), Mar 30 2001.
G.f.: exp(Sum_{k>=1} ( Sum_{d|k} d*(5^(k/d) - 1) ) * x^k/k). - Ilya Gutkovskiy, Sep 27 2018

A049316 The number k(GL(n,q)) of conjugacy classes in GL(n,q), q=7.

Original entry on oeis.org

1, 6, 48, 336, 2394, 16752, 117600, 823152, 5764416, 40350870, 282472512, 1977307248, 13841268048, 96888873648, 678222936384, 4747560552384, 33232929612330, 232630507267536, 1628413591207536, 11398895138319024, 79792266250574640, 558545863753891104
Offset: 0

Views

Author

Vladeta Jovovic

Keywords

References

  • V. Jovovic, The cycle index polynomials of some classical groups, Belgrade, 1995, unpublished.

Links

Crossrefs

Cf. A006951, A006952, A049314, A049315.

Programs

  • Magma
    /* The program does not work for n>8: */ [1] cat [NumberOfClasses(GL(n,7)): n in [1..8]]; // Sergei Haller (sergei(AT)sergei-haller.de), Dec 21 2006; edited by Vincenzo Librandi, Jan 23 2013
  • Maple
    with(numtheory):
b:= proc(n) b(n):= add(phi(d)*7^(n/d), d=divisors(n))/n-1 end:
a:= proc(n) a(n):= `if`(n=0, 1,
       add(add(d*b(d), d=divisors(j)) *a(n-j), j=1..n)/n)
    end:
seq(a(n), n=0..30);  # Alois P. Heinz, Nov 03 2012
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*7^(n/d), {d, Divisors[n]}]/n-1; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*b[d], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Jan 24 2014, after Alois P. Heinz *)
  • PARI
    x='x+O('x^30); Vec(prod(n=1, 30, (1-x^n)/(1-7*x^n))) \\ Altug Alkan, Sep 27 2018

Formula

The number a(n) of conjugacy classes in the group GL(n, q) is the coefficient of t^n in the infinite product: product k=1, 2, ... (1-t^k)/(1-qt^k) - Noam Katz (noamkj(AT)hotmail.com), Mar 30 2001.
G.f.: exp(Sum_{k>=1} ( Sum_{d|k} d*(7^(k/d) - 1) ) * x^k/k). - Ilya Gutkovskiy, Sep 27 2018

A182603 Number of conjugacy classes in GL(n,8).

Original entry on oeis.org

1, 7, 63, 504, 4088, 32697, 262080, 2096577, 16776648, 134213128, 1073737224, 8589897288, 68719439943, 549755515008, 4398046212672, 35184369697407, 281474974319672, 2251799794521144, 18014398490350584, 144115187922510840, 1152921504453534648
Offset: 0

Views

Author

Klaus Brockhaus, Nov 23 2010

Keywords

Links

Crossrefs

Cf. A006951, A006952, A049314, A049315, A049316, A182604 - A182612.

Programs

  • Magma
    /* The program does not work for n>6: */ [1] cat [NumberOfClasses(GL(n, 8)): n in [1..6]];
  • Maple
    with(numtheory):
b:= proc(n) b(n):= add(phi(d)*8^(n/d), d=divisors(n))/n-1 end:
a:= proc(n) a(n):= `if`(n=0, 1,
       add(add(d*b(d), d=divisors(j)) *a(n-j), j=1..n)/n)
    end:
seq(a(n), n=0..30);  # Alois P. Heinz, Nov 03 2012
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*8^(n/d), {d, Divisors[n]}]/n-1; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*b[d], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Feb 17 2014, after Alois P. Heinz *)

Formula

G.f.: prod((1-x^k)/(1-8*x^k),k=1..infinity).

Extensions

Extended by D. S. McNeil, Dec 06 2010
MAGMA code edited by Vincenzo Librandi, Jan 23 2013

A182604 Number of conjugacy classes in GL(n,9).

Original entry on oeis.org

1, 8, 80, 720, 6552, 58960, 531360, 4782160, 43045920, 387413208, 3486777120, 31380993360, 282429470960, 2541865231440, 22876791858720, 205891126722080, 1853020183479912, 16677181651254480, 150094635248646000, 1350851717237225040, 12157665458621220720
Offset: 0

Views

Author

Klaus Brockhaus, Nov 23 2010

Keywords

Links

Crossrefs

Cf. A006951, A006952, A049314, A049315, A049316, A182603, A182605, A182606, A182607, A182608, A182609, A182610, A182611, A182612.

Programs

  • Magma
    /* The program does not work for n>6: */ [1] cat [NumberOfClasses(GL(n, 9)): n in [1..6]];
  • Maple
    with(numtheory):
b:= proc(n) b(n):= add(phi(d)*9^(n/d), d=divisors(n))/n-1 end:
a:= proc(n) a(n):= `if`(n=0, 1,
       add(add(d*b(d), d=divisors(j)) *a(n-j), j=1..n)/n)
    end:
seq(a(n), n=0..30);  # Alois P. Heinz, Nov 03 2012
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*9^(n/d), {d, Divisors[n]}]/n-1; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*b[d], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Feb 17 2014, after Alois P. Heinz *)
  • PARI
    N=66; x='x+O('x^N);
gf=prod(n=1,N, (1-x^n)/(1-9*x^n)  );
v=Vec(gf)
/* Joerg Arndt, Jan 24 2013 */

Formula

G.f.: Product_{k>=1} (1-x^k)/(1-9*x^k). - Alois P. Heinz, Nov 03 2012

Extensions

More terms from Alois P. Heinz, Nov 03 2012
MAGMA code edited by Vincenzo Librandi, Jan 24 2013

A182605 Number of conjugacy classes in GL(n,11).

Original entry on oeis.org

1, 10, 120, 1320, 14630, 160920, 1771440, 19485720, 214357440, 2357931730, 25937408640, 285311493720, 3138428201160, 34522710196920, 379749831637440, 4177248147997440, 45949729842155150, 505447028263532520, 5559917313256631160, 61159090445821012920
Offset: 0

Views

Author

Klaus Brockhaus, Nov 23 2010

Keywords

Links

Crossrefs

Cf. A006951, A006952, A049314, A049315, A049316, A182603, A182604, A182606, A182607, A182608, A182609, A182610, A182611, A182612.

Programs

  • Magma
    N := 300;  R := PowerSeriesRing(Integers(), N);
Eltseq( &*[ (1-x^k)/(1-11*x^k) : k in [1..N] ] ); // Volker Gebhardt, Dec 07 2020
  • Maple
    with(numtheory):
b:= proc(n) b(n):= add(phi(d)*11^(n/d), d=divisors(n))/n-1 end:
a:= proc(n) a(n):= `if`(n=0, 1,
       add(add(d*b(d), d=divisors(j)) *a(n-j), j=1..n)/n)
    end:
seq(a(n), n=0..30);  # Alois P. Heinz, Nov 03 2012
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*11^(n/d), {d, Divisors[n]}]/n-1; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*b[d], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Feb 17 2014, after Alois P. Heinz *)
  • PARI
    N=66; x='x+O('x^N);
gf=prod(n=1,N, (1-x^n)/(1-11*x^n)  );
v=Vec(gf)
/* Joerg Arndt, Jan 24 2013 */

Formula

G.f.: Product_{k>=1} (1-x^k)/(1-11*x^k). - Alois P. Heinz, Nov 03 2012

Extensions

More terms from Alois P. Heinz, Nov 03 2012

A182606 Number of conjugacy classes in GL(n,13).

Original entry on oeis.org

1, 12, 168, 2184, 28548, 371112, 4826640, 62746152, 815728368, 10604468628, 137858461104, 1792159992168, 23298084722808, 302875101365928, 3937376380474992, 51185892946146672, 665416609115237772, 8650415918497693704, 112455406951074120024
Offset: 0

Views

Author

Klaus Brockhaus, Nov 23 2010

Keywords

Links

Crossrefs

Cf. A006951, A006952, A049314, A049315, A049316, A182603, A182604, A182605, A182607, A182608, A182609, A182610, A182611, A182612.

Programs

  • Magma
    /* The program does not work for n>5: */ [1] cat [NumberOfClasses(GL(n, 13)): n in [1..5]];
  • Maple
    with(numtheory):
b:= proc(n) b(n):= add(phi(d)*13^(n/d), d=divisors(n))/n-1 end:
a:= proc(n) a(n):= `if`(n=0, 1,
       add(add(d*b(d), d=divisors(j)) *a(n-j), j=1..n)/n)
    end:
seq(a(n), n=0..30);  # Alois P. Heinz, Nov 03 2012
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*13^(n/d), {d, Divisors[n]}]/n-1; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*b[d], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Feb 17 2014, after Alois P. Heinz *)
  • PARI
    N=66; x='x+O('x^N);
gf=prod(n=1,N, (1-x^n)/(1-13*x^n)  );
v=Vec(gf)
/* Joerg Arndt, Jan 24 2013 */

Formula

G.f.: Product_{k>=1} (1-x^k)/(1-13*x^k). - Alois P. Heinz, Nov 03 2012

Extensions

More terms from Alois P. Heinz, Nov 03 2012
MAGMA code edited by Vincenzo Librandi, Jan 24 2013

A182607 Number of conjugacy classes in GL(n,16).

Original entry on oeis.org

1, 15, 255, 4080, 65520, 1048305, 16776960, 268431105, 4294962960, 68719407120, 1099511558160, 17592184926480, 281474975596815, 4503599609479680, 72057594020040960, 1152921504320590335, 18446744073423298800, 295147905174771671280, 4722366482865065107440
Offset: 0

Views

Author

Klaus Brockhaus, Nov 23 2010

Keywords

Links

Crossrefs

Cf. A006951, A006952, A049314, A049315, A049316, A182603, A182604, A182605, A182606, A182608, A182609, A182610, A182611, A182612.

Programs

  • Magma
    /* The program does not work for n>6: */ [1] cat [NumberOfClasses(GL(n, 16)) : n in [1..6]];
  • Maple
    with(numtheory):
b:= proc(n) b(n):= add(phi(d)*16^(n/d), d=divisors(n))/n-1 end:
a:= proc(n) a(n):= `if`(n=0, 1,
       add(add(d*b(d), d=divisors(j)) *a(n-j), j=1..n)/n)
    end:
seq(a(n), n=0..30);  # Alois P. Heinz, Nov 03 2012
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*16^(n/d), {d, Divisors[n]}]/n-1; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*b[d], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Feb 17 2014, after Alois P. Heinz *)
  • PARI
    N=66; x='x+O('x^N);
gf=prod(n=1,N, (1-x^n)/(1-16*x^n)  );
v=Vec(gf)
/* Joerg Arndt, Jan 24 2013 */

Formula

G.f.: Product_{k>=1} (1-x^k)/(1-16*x^k). - Alois P. Heinz, Nov 03 2012

Extensions

More terms from Alois P. Heinz, Nov 03 2012
MAGMA code edited by Vincenzo Librandi, Jan 24 2013
Showing 1-10 of 24 results. Next

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