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 1-7 of 7 results.

A090091 Number of groups of order 3^n.

Original entry on oeis.org

1, 1, 2, 5, 15, 67, 504, 9310, 1396077, 5937876645
Offset: 0

Views

Author

Eamonn O'Brien, Jan 22 2004

Keywords

Examples

			G.f. = 1 + x + 2*x^2 + 5*x^3 + 15*x^4 + 67*x^5 + 504*x^6 + 9310*x^7 + ...
		

References

  • G. Bagnera, La composizione dei Gruppi finiti il cui grado e la quinta potenza di un numero primo, Ann. Mat. Pura Appl. (3), 1 (1898), 137-228.
  • Hans Ulrich Besche, Bettina Eick and E. A. O'Brien, A Millennium Project: Constructing Small Groups, International Journal of Algebra and Computation, Vol. 12, No 5 (2002), 623-644.
  • W. Burnside, Theory of Groups of Finite Order, Dover, NY, 1955.
  • Marcus du Sautoy, Symmetry: A Journey into the Patterns of Nature, HarperCollins, 2008, p. 96.

Crossrefs

Programs

Formula

a(n) = A000001(3^n).

Extensions

a(7) from David Radcliffe, Feb 24 2010
a(8) from Muniru A Asiru, Oct 17 2018
a(9) from David Burrell, Sep 01 2023

A090130 Number of groups of order 5^n.

Original entry on oeis.org

1, 1, 2, 5, 15, 77, 684, 34297
Offset: 0

Views

Author

Eamonn O'Brien, Jan 22 2004

Keywords

References

  • G. Bagnera, La composizione dei Gruppi finiti il cui grado e la quinta potenza di un numero primo, Ann. Mat. Pura Appl. (3), 1 (1898), 137-228.
  • Hans Ulrich Besche, Bettina Eick and E. A. O'Brien, A Millennium Project: Constructing Small Groups, International Journal of Algebra and Computation, Vol. 12, No 5 (2002), 623-644.
  • W. Burnside, Theory of Groups of Finite Order, Dover, NY, 1955.

Crossrefs

Programs

Formula

For a prime p >= 5, the number of groups of order p^n begins 1, 1, 2, 5, 15, 61 + 2*p + 2*gcd (p - 1, 3) + gcd (p - 1, 4), 3*p^2 + 39*p + 344 + 24*gcd(p - 1, 3) + 11*gcd(p - 1, 4) + 2*gcd(p - 1, 5), ...

Extensions

Corrected and extended by David Radcliffe, Feb 24 2010
Corrected and extended by Eamonn O'Brien, Mar 06 2010

A232106 Number of groups of order prime(n)^6.

Original entry on oeis.org

267, 504, 684, 860, 1192, 1476, 1944, 2264, 2876, 4068, 4540, 6012, 7064, 7664, 8852, 10908, 13136, 14012, 16520, 18292, 19296, 22244, 24296, 27648, 32472, 34964, 36284, 38912, 40356, 43128, 53780, 56992, 62064, 63824, 72828, 74740, 80532, 86504, 90572, 96948
Offset: 1

Views

Author

Eric M. Schmidt, Nov 21 2013

Keywords

Comments

Isomorphism types of groups and nilpotent Lie rings with order prime(n)^6.

Crossrefs

Programs

  • GAP
    A232106 := Concatenation([267, 504], List(Filtered([5..10^5], IsPrime), p -> 3 * p^2 + 39 * p + 344 + 24 * Gcd(p-1, 3) + 11 * Gcd(p-1, 4) + 2 * Gcd(p-1, 5))); # Muniru A Asiru, Nov 16 2017
  • Maple
    a:= n-> `if`(n<3, [267, 504][n], (c-> 386 +(45 +3*c)*c+
        24*igcd(c, 3) +11*igcd(c, 4) +2*igcd(c, 5))(ithprime(n)-1)):
    seq(a(n), n=1..40);  # Alois P. Heinz, Nov 17 2017
  • Mathematica
    Table[FiniteGroupCount[Prime[n]^6], {n, 40}] (* Michael De Vlieger, Apr 12 2016 *)
  • PARI
    a(n) = if(n==1, 267, if (n==2, 504, my(p=prime(n)); 3*p^2 + 39*p + 344 + 24*gcd(p - 1, 3) + 11*gcd(p - 1, 4) + 2*gcd(p - 1, 5))); \\ Altug Alkan, Apr 12 2016
    
  • Sage
    def A232106(n) : p = nth_prime(n); return 267 if p==2 else 504 if p==3 else 3*p^2 + 39*p + 344 + 24*gcd(p - 1, 3) + 11*gcd(p - 1, 4) + 2*gcd(p - 1, 5)
    

Formula

For a prime p > 3, the number of groups of order p^6 is 3p^2 + 39p + 344 + 24 gcd(p - 1, 3) + 11 gcd(p - 1, 4) + 2 gcd(p - 1, 5).

A232105 Number of groups of order prime(n)^5.

Original entry on oeis.org

51, 67, 77, 83, 87, 97, 101, 107, 111, 125, 131, 145, 149, 155, 159, 173, 183, 193, 203, 207, 217, 227, 231, 245, 265, 269, 275, 279, 289, 293, 323, 327, 341, 347, 365, 371, 385, 395, 399, 413, 423, 433, 447, 457, 461, 467, 491, 515, 519, 529, 533, 543, 553
Offset: 1

Views

Author

Eric M. Schmidt, Nov 21 2013

Keywords

Crossrefs

Programs

  • GAP
    A232105 := Concatenation([51, 67], List(Filtered([5..10^5], IsPrime), p -> 61 + 2 * p + 2 * Gcd(p-1, 3) + Gcd(p-1, 4))); # Muniru A Asiru, Nov 16 2017
  • Sage
    def A232105(n) : p = nth_prime(n); return 51 if p==2 else 67 if p==3 else 61 + 2*p + 2*gcd(p - 1, 3) + gcd(p - 1, 4)
    

Formula

For a prime p > 3, the number of groups of order p^5 is 61 + 2p + 2 gcd(p - 1, 3) + gcd(p - 1, 4).

A232107 Number of groups of order prime(n)^7.

Original entry on oeis.org

2328, 9310, 34297, 113147, 750735, 1600573, 5546909, 9380741, 23316851, 71271069, 98488755, 233043067, 384847485, 485930975, 751588475, 1356370173, 2299880351, 2710679045, 4306310927, 5734323819, 6578172579, 9721485395, 12413061671, 17537591045, 26866372821
Offset: 1

Views

Author

Eric M. Schmidt, Nov 21 2013

Keywords

Crossrefs

Programs

  • GAP
    A232107 := Concatenation([2328, 9310, 34297], List(Filtered([7..10^5], IsPrime), p -> 3 * p^5 + 12 * p^4 + 44 * p^3 + 170 * p^2 + 707 * p + 2455 + (4 * p^2 + 44 * p + 291) * Gcd(p-1, 3) + (p^2 + 19 * p + 135) * Gcd(p-1, 4) + (3 * p + 31) * Gcd(p-1, 5) + 4 *  Gcd(p-1, 7) + 5 * Gcd(p-1, 8) +  Gcd(p-1, 9))); # Muniru A Asiru, Nov 16 2017
  • Maple
    a:= n-> `if`(n<4, [2328, 9310, 34297][n], (c-> 3391 +(1242+
        (404 +(122 +(27 +3*c)*c)*c)*c)*c +(339 +(52 +4*c)*c)*igcd(c, 3)+
        (155 +(21 +c)*c)*igcd(c, 4) +(34 +3*c)*igcd(c, 5) +4*igcd(c, 7)+
         5*igcd(c, 8) +igcd(c, 9))(ithprime(n)-1)):
    seq(a(n), n=1..25);  # Alois P. Heinz, Nov 17 2017
  • Sage
    def A232107(n) : p = nth_prime(n); return 2328 if p==2 else 9310 if p==3 else 34297 if p==5 else 3*p^5 + 12*p^4 + 44*p^3 + 170*p^2 + 707*p + 2455 + (4*p^2 + 44*p + 291)*gcd(p - 1, 3) + (p^2 + 19*p + 135)*gcd(p - 1, 4) + (3*p + 31)*gcd(p - 1, 5) + 4*gcd(p - 1, 7) + 5*gcd(p - 1, 8) + gcd(p - 1, 9)
    

Formula

For a prime p > 5, the number of groups of order p^7 is 3p^5 + 12p^4 + 44p^3 + 170p^2 + 707p + 2455 + (4p^2 + 44p + 291)gcd(p - 1, 3) + (p^2 + 19p + 135)gcd(p - 1, 4) + (3p + 31)gcd(p - 1, 5) + 4 gcd(p - 1, 7) + 5 gcd(p - 1, 8) + gcd(p - 1, 9).

A252787 Number of exponent-7 class 2 groups of order 7^n.

Original entry on oeis.org

0, 0, 1, 3, 7, 28, 131, 26465, 2832610615, 18602165186505644, 1577146952504975321253720851
Offset: 0

Views

Author

Eric M. Schmidt, Dec 21 2014

Keywords

Crossrefs

A319171 Square array, read by antidiagonals, upwards: T(n,k) is the number of groups of order prime(k+1)^n.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 5, 2, 1, 1, 14, 5, 2, 1, 1, 51, 15, 5, 2, 1, 1, 267, 67, 15, 5, 2, 1, 1, 2328, 504, 77, 15, 5, 2, 1, 1, 56092, 9310, 684, 83, 15, 5, 2, 1, 1, 10494213, 1396077, 34297, 860, 87, 15, 5, 2, 1, 1, 49487367289, 5937876645
Offset: 0

Views

Author

Keywords

Comments

In 1960, Higman conjectured that the function f(n,p) giving the number of groups of prime-power order p^n, for fixed n and varying p, is a "Polynomial in Residue Classes" (PORC), i.e., there exist an integer M and polynomials q_i(x) in Z[x] (i = 1, 2, ..., M) such that if p = i mod M, then f(n,p) = q_i(p). The conjecture is confirmed for n <= 7.

Examples

			Array begins:
  (p = 2) (p = 3) (p = 5) (p = 7) (p = 11) (p = 13) ...
       1       1       1       1        1        1  ...
       1       1       1       1        1        1  ...
       2       2       2       2        2        2  ...
       5       5       5       5        5        5  ...
      14      15      15      15       15       15  ...
      51      67      77      83       87       97  ...
     267     504     684     860     1192     1476  ...
    2328    9310   34297  113147   750735  1600573  ...
     ...
		

Crossrefs

Programs

  • GAP
    # This program computes the first 45 terms, rows 0..8.
    P:=Filtered([1..300],IsPrime);;
    T1:=List([0..7],n->List([0..15],k->NumberSmallGroups(P[k+1]^n)));;
    T2:=[Flat(Concatenation(List([8],n->List([0],k->NumberSmallGroups(P[k+1]^n))),List([1..14],i->0)))];;
    T:=Concatenation(T1,T2);;
    b:=List([2..10],n->OrderedPartitions(n,2));;
    a:=Flat(List([1..Length(b)],i->List([1..Length(b[i])],j->T[b[i][j][2]][b[i][j][1]]))); # Muniru A Asiru, Oct 01 2018
  • Maple
    with(GroupTheory): T:=proc(n,k) NumGroups(ithprime(k+1)^n); end proc: seq(seq(T(n-k,k),k=0..n),n=0..10); # Muniru A Asiru, Oct 03 2018
  • Mathematica
    (* This program uses Higman's PORC functions to compute the rows 0 to 7 *)
    f[0, p_] := 1; f[1, p_] := 1; f[2, p_] := 2; f[3, p_] := 5;
    f[4, p_] := If[p == 2, 14, 15];
    f[5, p_] := If[p == 2, 51, If[p == 3, 67, 61 + 2*p + 2*GCD[p - 1, 3] + GCD[p - 1, 4]]];
    f[6, p_] := If[p == 2, 267, If[p == 3, 504, 3*p^2 + 39*p + 344 + 24*GCD[p - 1, 3] + 11*GCD[p - 1, 4] + 2*GCD[p - 1, 5]]];
    f[7, p_] := If[p == 2, 2328, If[p == 3, 9310, If[p == 5, 34297, 3*p^5 + 12*p^4 + 44*p^3 + 170*p^2 + 707*p + 2455 + (4*p^2 + 44*p + 291)*GCD[p - 1, 3] + (p^2 + 19*p + 135)*GCD[p - 1, 4] + (3*p + 31)*GCD[p - 1, 5] + 4*GCD[p - 1, 7] + 5*GCD[p - 1, 8] + GCD[p - 1, 9]]]];
    tabl[kk_] := TableForm[Table[f[n, Prime[k+1]], {n, 0, 7}, {k, 0, kk}]];

Formula

T(n,0) = A000679(n).
T(n,1) = A090091(n).
T(n,2) = A090130(n).
T(n,3) = A090140(n).
T(0,n) = 1, T(1,n) = 1, T(2,n) = 2 and T(3,n) = 5.
T(4,0) = 14 and T(4,n) = 15, n > 0.
T(5,n) = A232105(n+1).
T(6,n) = A232106(n+1).
T(7,n) = A232107(n+1).

Extensions

a(55)=T(10,0) corrected by David Burrell, Jun 07 2022
a(56)=T(9,1) from David Burrell, Sep 01 2023
Showing 1-7 of 7 results.