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.

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).

A269748 a(n) = 2*p+61+2*gcd(p-1,3)+gcd(p-1,4), where p = prime(n).

Original entry on oeis.org

68, 71, 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, 567, 581, 591, 605, 611, 625, 629
Offset: 1

Views

Author

N. J. A. Sloane, Mar 22 2016

Keywords

Programs

  • Magma
    [2*p+61 +2*Gcd(p-1,3)+Gcd(p-1,4): p in PrimesUpTo(700)]; // Vincenzo Librandi, Mar 26 2016
  • Maple
    f1:=proc(n) local p; p:=ithprime(n);
    2*p+61+2*gcd(p-1,3)+gcd(p-1,4);
    end;
  • Mathematica
    Table[2 Prime[n] + 61 + 2 GCD[Prime[n] - 1, 3] + GCD[Prime[n] -1, 4], {n, 60}] (* Vincenzo Librandi, Mar 26 2016 *)

Formula

a(n) = A232106(n) for n>=3. - R. J. Mathar, Jun 21 2025

A269749 a(n) = 3*p^2+39*p+344+24*gcd(p-1,3)+11*gcd(p-1,4)+2*gcd(p-1,5), where p = prime(n).

Original entry on oeis.org

471, 536, 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, 103496, 105812, 117292, 119736
Offset: 1

Views

Author

N. J. A. Sloane, Mar 22 2016

Keywords

Programs

  • Magma
    [3*p^2 + 39*p + 344 + 24*Gcd(p-1, 3) + 11*Gcd(p-1, 4) + 2*Gcd(p-1, 5): p in PrimesUpTo(200)]; // Vincenzo Librandi, Mar 26 2016
  • Maple
    f2:=proc(n) local p; p:=ithprime(n);
    3*p^2+39*p+344+24*gcd(p-1,3)+11*gcd(p-1,4)+2*gcd(p-1,5);
    end;
    [seq(f2(n),n=1..60)];
  • Mathematica
    Table[3 Prime[n]^2 + 39 Prime[n] + 344 + 24 GCD[Prime[n] - 1, 3]+ 11 GCD[Prime[n] - 1, 4] + 2 GCD[Prime[n] - 1, 5], {n, 45}] (* Vincenzo Librandi, Mar 26 2016 *)

Formula

a(n) = A232106(n), n>2. - R. J. Mathar, May 23 2016

A271664 Erroneous version of A271811 (but for odd primes only).

Original entry on oeis.org

491, 668, 844, 1183, 1474, 1961, 2293, 2936, 4190, 4686, 6244, 7363, 7999, 9266, 11456, 13835, 14766, 17449, 19348, 20419, 23578, 25781, 29375, 34549, 37228, 38644, 41471, 43018, 46001, 57454, 60913, 66371, 68263, 77960, 80016, 86254, 92689, 97076, 103946, 111005, 113496
Offset: 2

Views

Author

Michel Marcus, Apr 12 2016

Keywords

Comments

Previous name was "Number of non-abelian groups of order prime(n)^6".

Crossrefs

Cf. A000001 (groups), A060689 (non-abelian groups),
Cf. A030516 (primes^6)
Cf. A271811.

Programs

  • PARI
    a(n) = if (n==2, 491, my(p=prime(n)); (13*p^2 + 145*p + 1338 + 80*gcd(p-1, 3) + 45*gcd(p-1, 4) + 8*gcd(p-1, 5) + 8*gcd(p-1, 6))/4);

Formula

a(n) = (13*p^2 + 145*p + 1338 + 80*gcd(p-1,3) + 45*gcd(p-1,4) + 8*gcd(p-1, 5) + 8*gcd(p-1,6))/4 for n>2 and where p = prime(n). See [Rodney James].

A271811 Number of non-abelian groups of order prime(n)^6.

Original entry on oeis.org

256, 493, 673, 849, 1181, 1465, 1933, 2253, 2865, 4057, 4529, 6001, 7053, 7653, 8841, 10897, 13125, 14001, 16509, 18281, 19285, 22233, 24285, 27637, 32461, 34953, 36273, 38901, 40345, 43117, 53769, 56981, 62053, 63813, 72817, 74729, 80521, 86493, 90561, 96937, 103485, 105801, 117281
Offset: 1

Views

Author

Altug Alkan, Apr 14 2016

Keywords

Comments

A000688(p^6) is 11 for all prime p.

Crossrefs

Programs

  • GAP
    A271811 := Concatenation([256, 493], List(Filtered([5..10^4], IsPrime), p -> 3 * p^2 + 39 * p + 333 + 24 * Gcd(p-1, 3) + 11 * Gcd(p-1, 4) + 2 * Gcd(p-1,5))); # Muniru A Asiru, Nov 18 2017
  • Mathematica
    Table[FiniteGroupCount[#] - FiniteAbelianGroupCount[#] &[Prime[n]^6], {n, 43}] (* Michael De Vlieger, Apr 15 2016, after Vladimir Joseph Stephan Orlovsky at A060689 *)
  • PARI
    a(n) = if (n==1, 256, if (n==2, 493, my(p=prime(n)); 3*p^2 + 39*p + 333 + 24*gcd(p - 1, 3) + 11*gcd(p - 1, 4) + 2*gcd(p - 1, 5)));
    

Formula

a(n) = A232106(n) - 11.
a(n) = A060689(prime(n)^6) = A060689(A030516(n)).
For a prime p > 3, the number of non-abelian groups of order p^6 is 3p^2 + 39p + 333 + 24 gcd(p - 1, 3) + 11 gcd(p - 1, 4) + 2 gcd(p - 1, 5).

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.