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 15 results. Next

A129766 Triangular array read by rows, made up of traditional exceptional groups plus A1: as A1,G2,F4,E6,E7,E8 as m(i) exponents as in A005556, A005763, A005776.

Original entry on oeis.org

1, 1, 5, 1, 5, 7, 11, 1, 4, 5, 7, 8, 11, 1, 5, 7, 9, 11, 13, 17, 1, 7, 11, 13, 17, 19, 23, 29
Offset: 1

Views

Author

Roger L. Bagula, May 16 2007

Keywords

Comments

Extra condition of group dimension: b[n] = a[n] + 1 ; DimGroup = Apply[Plus, b[n]]; Table[Apply[Plus, b[n]], {n, 0, 5}] {3, 14, 52, 78, 133, 248} Extra condition of Betti sum: Table[Apply[Plus, CoefficientList[Expand[Product[(1 + t^(2*a[i][[n]] + 1)), {n, 1,Length[a[i]]}]], t]], {i, 0, 5}] {2, 4, 16, 64, 128, 256} These exponents are necessary to the Poincaré polynomials for these exceptional groups.

Examples

			1;
1,5;
1,5,7,11;
1,4,5,7,8,11;
1,5,7,9,11,13,17;
1,7,11,13,17,19,23,29;
		

Crossrefs

Programs

  • Mathematica
    a[0] = {1}; a[1] = {1, 5}; a[2] = {1, 5, 7, 11}; a[3] = {1, 4, 5, 7, 8, 11}; a[4] = {1, 5, 7, 9, 11, 13, 17}; a[5] = {1, 7, 11, 13, 17, 19, 23, 29}; Flatten[Table[a[n], {n, 0, 5}]]

A100418 Numbers k such that 30*k + {1,11,13,17,19,23,29} are all prime.

Original entry on oeis.org

49, 34083, 41545, 48713, 140609, 524027, 616812, 855281, 1314397, 1324750, 1636152, 2281293, 2927134, 3401412, 3605413, 4989341, 5212221, 5284979, 5406303, 5645269, 6141254, 6342728, 7231434, 7347697, 7637329, 8027068, 8161657, 8372756, 8392776, 8567216, 8986096, 9145563
Offset: 1

Views

Author

Ferenc Adorjan (fadorjan(AT)freemail.hu), Nov 19 2004

Keywords

Comments

Values are 0 mod 7.
From Peter Munn, Sep 06 2023: (Start)
In each case, the 7 primes are necessarily consecutive.
As A065706 demonstrates, many intervals of 27 integers contain 8 primes, but only A364678(30) = 7 primes can occur between adjacent positive multiples of 30. This is because there are 8 values {1,7,11,13,17,19,23,29} coprime to 30, but they cover every residue class modulo 7, which means at least one of 30*k + {1,7,11,13,17,19,23,29} is divisible by 7.
1 and 29 are in the same residue class, but if we remove any of the other coprime integers there is a class that is not represented in the set. For this sequence, we remove 7, so when k is a multiple of 7, none of 30*k + {1,11,13,17,19,23,29} is a multiple of 2, 3, 5 or 7 and the set can potentially be 7 consecutive primes.
The sequences for the other appropriate subsets of 7 coprime values are A100419-A100423.
(End)

Crossrefs

Programs

  • Magma
    [ n: n in [0..70000000 by 7] | forall{ q: q in [1, 11, 13, 17, 19, 23, 29] | IsPrime(30*n+q) } ]; // Klaus Brockhaus, Feb 24 2011
  • Mathematica
    Select[Range[803*10^4],AllTrue[30#+{1,11,13,17,19,23,29},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jun 11 2019 *)
  • PARI
    {pav7(mx)= local(wp=[1,11,13,17,19,23,29],v=[],i,j,m); for(k=1,mx, i=k*30;j=1;m=1;while(m&&(j<8),m=isprime(i+wp[j]);j+=1);if(m,v=concat(v,k))); return(v)}
    

Extensions

Edited by Don Reble, Nov 17 2005

A100423 Numbers n such that 30*n+{1,7,11,13,17,19,29} are all prime.

Original entry on oeis.org

62, 188, 9491, 31982, 38226, 38520, 89459, 168237, 175125, 368248, 471078, 634892, 704416, 803102, 994748, 1436315, 1488857, 1605484, 1842553, 1945824, 2282958, 2465266, 2620715, 2627029, 2705037, 4282305, 5569899, 5914824
Offset: 1

Views

Author

Ferenc Adorjan (fadorjan(AT)freemail.hu), Nov 19 2004

Keywords

Comments

Values are 6 mod 7.
In each case, the 7 primes are necessarily consecutive. See the comment in A100418. - Peter Munn, Sep 06 2023

Crossrefs

Programs

  • Magma
    [ n: n in [0..6000000] | forall{ q: q in [1, 7, 11, 13, 17, 19, 29] | IsPrime(30*n+q) } ]; // Klaus Brockhaus, Feb 24 2011
  • Mathematica
    Select[Range[6*10^6],AllTrue[30#+{1,7,11,13,17,19,29},PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 21 2021 *)

Extensions

Edited by Don Reble, Nov 17 2005

A076205 Numbers n such that 30*n+{1,7,11,13,17,19,23,29} are all composite.

Original entry on oeis.org

360, 523, 654, 941, 1020, 1047, 1064, 1136, 1188, 1213, 1264, 1280, 1343, 1355, 1445, 1477, 1515, 1526, 1530, 1533, 1582, 1623, 1652, 1693, 1842, 1900, 1960, 2018, 2039, 2129, 2208, 2280, 2309, 2332, 2406, 2413, 2440, 2499, 2539, 2622, 2633, 2650, 2657
Offset: 1

Views

Author

Donald S. McDonald, Nov 02 2002

Keywords

References

  • H. S. M. Coxeter and W. O. J. Moser, Generators and Relations for Discrete Groups, 4th ed., Springer-Verlag, NY, reprinted 1984, p. 141.

Crossrefs

Programs

  • Magma
    [ n: n in [0..3000] | forall{ q: q in [1, 7, 11, 13, 17, 19, 23, 29] | not IsPrime(30*n+q) } ]; // Klaus Brockhaus, Feb 24 2011
  • Mathematica
    Select[Range[3000],AllTrue[30#+{1,7,11,13,17,19,23,29},CompositeQ]&] (* Harvey P. Dale, Jan 06 2022 *)
  • PARI
    {cav(mx)= local(wp=[1,7,11,13,17,19,23,29],v=[],i,j,m); for(k=1,mx, i=k*30;j=1;m=1;while(m&&(j<9),m=!isprime(i+wp[j]);j+=1);if(m,v=concat(v,k))); return(v)}
    

Extensions

More terms from Ferenc Adorjan (fadorjan(AT)freemail.hu), Nov 19 2004
Edited by Don Reble, Nov 17 2005
Edited by N. J. A. Sloane, Sep 14 2008 at the suggestion of R. J. Mathar

A106403 Primitive exponents of the Weyl group W(E_8).

Original entry on oeis.org

3, 15, 23, 27, 35, 39, 47, 59
Offset: 1

Views

Author

N. J. A. Sloane, May 30 2005

Keywords

References

  • C. Chevalley, The Betti numbers of the exceptional Lie groups, pp. 21-24 of Proc. Internat Congress Math., Cambridge 1950, Amer. Math. Soc., 1952.

Crossrefs

Formula

Equals 2*A005776(n) + 1.

A100419 Numbers k such that 30*k+{1,7,13,17,19,23,29} are all prime.

Original entry on oeis.org

89, 6627, 18674, 223949, 229269, 240007, 267356, 606681, 638454, 771496, 951060, 1068030, 1150693, 1254839, 1688923, 1920084, 2413577, 2433289, 2649414, 3053398, 3080572, 3337444, 3586658, 3604256, 3830335, 4137166
Offset: 1

Views

Author

Ferenc Adorjan (fadorjan(AT)freemail.hu), Nov 19 2004

Keywords

Comments

Values are 5 mod 7.
In each case, the 7 primes are necessarily consecutive. See the comment in A100418. - Peter Munn, Sep 06 2023

Crossrefs

Programs

  • Magma
    [ n: n in [5..70000000 by 7] | forall{ q: q in [1, 7, 13, 17, 19, 23, 29] | IsPrime(30*n+q) } ]; // Klaus Brockhaus, Feb 24 2011
  • Maple
    filter:= proc(n) local j; andmap(isprime, [seq(30*n+j,j=[1,7,13,17,19,23,29])]) end proc:
    select(filter, [seq(i,i=5..5*10^6,7)]); # Robert Israel, Nov 04 2024
  • Mathematica
    Select[Range[42*10^5],AllTrue[30#+{1,7,13,17,19,23,29},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Mar 10 2018 *)

Extensions

Edited by Don Reble, Nov 17 2005

A106373 Primitive exponents of the Weyl group W(E_6).

Original entry on oeis.org

3, 9, 11, 15, 17, 23
Offset: 1

Views

Author

N. J. A. Sloane, May 30 2005

Keywords

References

  • C. Chevalley, The Betti numbers of the exceptional Lie groups, pp. 21-24 of Proc. Internat Congress Math., Cambridge 1950, Amer. Math. Soc., 1952.

Crossrefs

Formula

Equals 2*A005556(n) + 1.

A106374 Primitive exponents of the Weyl group W(E_7).

Original entry on oeis.org

3, 11, 15, 19, 23, 27, 35
Offset: 1

Views

Author

N. J. A. Sloane, May 30 2005

Keywords

References

  • C. Chevalley, The Betti numbers of the exceptional Lie groups, pp. 21-24 of Proc. Internat Congress Math., Cambridge 1950, Amer. Math. Soc., 1952.

Crossrefs

Formula

Equals 2*A005763(n) + 1.

A089010 a(n) = 1 if n is an exponent of the Weyl group W(E_8), 0 otherwise.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Paul Boddington, Nov 03 2003

Keywords

Comments

The exponents are 1, 7, 11, 13, 17, 19, 23, 29. The point of this sequence is that a similar generating function gives the exponents for any finite Coxeter group.

Crossrefs

Programs

  • Mathematica
    PadRight[CoefficientList[Series[x(1-x^20)(1-x^24)/((1-x^6)(1-x^10)),{x,0,120}],x],120,0] (* Harvey P. Dale, May 15 2018 *)
  • PARI
    Vec(x*(1-x^20)*(1-x^24)/((1-x^6)*(1-x^10)) + O(x^90)) \\ Michel Marcus, Aug 19 2015

Formula

G.f.: x*(1-x^20)*(1-x^24)/((1-x^6)*(1-x^10)).

A100420 Numbers n such that 30*n+{1,7,11,17,19,23,29} are all prime.

Original entry on oeis.org

22621, 103205, 149125, 237794, 288467, 321451, 364921, 373370, 404002, 851099, 985933, 1106235, 1594044, 1696874, 1780265, 1824421, 1851756, 2249881, 3112939, 3257538, 3397608, 3601651, 3747356, 4347340, 4710990, 4886284
Offset: 1

Views

Author

Ferenc Adorjan (fadorjan(AT)freemail.hu), Nov 19 2004

Keywords

Comments

Values are 4 mod 7.
In each case, the 7 primes are necessarily consecutive. See the comment in A100418. - Peter Munn, Sep 06 2023

Crossrefs

Programs

  • Magma
    [ n: n in [4..70000000 by 7] | forall{ q: q in [1, 7, 11, 17, 19, 23, 29] | IsPrime(30*n+q) } ]; // Klaus Brockhaus, Feb 24 2011
  • Mathematica
    Select[Range[5000000],And@@PrimeQ[30 #+{1,7,11,17,19,23,29}]&]  (* Harvey P. Dale, Mar 06 2011 *)

Extensions

Edited by Don Reble, Nov 17 2005
Showing 1-10 of 15 results. Next