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.

Previous Showing 11-18 of 18 results.

A221578 A sum over partitions (q=6), see first comment.

Original entry on oeis.org

1, 5, 35, 210, 1290, 7735, 46620, 279685, 1679370, 10076190, 60464670, 362787810, 2176773305, 13060638360, 78364108620, 470184650495, 2821109573550, 16926657432510, 101559954663930, 609359727929610, 3656158427989830, 21936950567886270, 131621703769781995
Offset: 0

Views

Author

Joerg Arndt, Jan 20 2013

Keywords

Comments

Set q=6 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].
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:
q=6: A221578, q=10: A221579, q=12: A221580,
q=14: A221581, q=15: A221582, q=18: A221583, q=20: A221584.

Programs

  • Maple
    with(numtheory):
    b:= proc(n) b(n):= add(phi(d)*6^(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, Jan 24 2013
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*6^(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)/(1-6*x^n)  );
    v=Vec(gf)

A221579 A sum over partitions (q=10), see first comment.

Original entry on oeis.org

1, 9, 99, 990, 9990, 99891, 999900, 9998901, 99998910, 999989010, 9999989010, 99999889110, 999999890109, 9999998890200, 99999998891100, 999999988901199, 9999999988902090, 99999999888912090, 999999999889011990, 9999999998889021990
Offset: 0

Views

Author

Joerg Arndt, Jan 20 2013

Keywords

Comments

Set q=10 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].
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:
q=6: A221578, q=10: A221579, q=12: A221580,
q=14: A221581, q=15: A221582, q=18: A221583, q=20: A221584.

Programs

  • Maple
    with(numtheory):
    b:= proc(n) b(n):= add(phi(d)*10^(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, Jan 25 2013
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*10^(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)/(1-10*x^n)  );
    v=Vec(gf)

A221580 A sum over partitions (q=12), see first comment.

Original entry on oeis.org

1, 11, 143, 1716, 20724, 248677, 2985840, 35829937, 429979836, 5159757900, 61917341772, 743008099548, 8916100178843, 106993202123808, 1283918461295184, 15407021535521759, 184884258855973380, 2218611106271412996, 26623333280416468596, 319479999364994391924
Offset: 0

Views

Author

Joerg Arndt, Jan 20 2013

Keywords

Comments

Set q=12 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].
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:
q=6: A221578, q=10: A221579, q=12: A221580,
q=14: A221581, q=15: A221582, q=18: A221583, q=20: A221584.

Programs

  • Maple
    with(numtheory):
    b:= proc(n) b(n):= add(phi(d)*12^(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, Feb 03 2013
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*12^(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)/(1-12*x^n)  );
    v=Vec(gf)

A221581 A sum over partitions (q=14), see first comment.

Original entry on oeis.org

1, 13, 195, 2730, 38402, 537615, 7529340, 105410565, 1475786130, 20661005638, 289254613830, 4049564590890, 56693911799265, 793714765148760, 11112006817455180, 155568095444334495, 2177953337695895942, 30491346727741970070, 426878854209048054450
Offset: 0

Views

Author

Joerg Arndt, Jan 20 2013

Keywords

Comments

Set q=14 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].
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:
q=6: A221578, q=10: A221579, q=12: A221580,
q=14: A221581, q=15: A221582, q=18: A221583, q=20: A221584.

Programs

  • Maple
    with(numtheory):
    b:= proc(n) b(n):= add(phi(d)*14^(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, Feb 03 2013
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*14^(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)/(1-14*x^n)  );
    v=Vec(gf)

A221582 A sum over partitions (q=15), see first comment.

Original entry on oeis.org

1, 14, 224, 3360, 50610, 759136, 11390400, 170855776, 2562887040, 38443305390, 576650336640, 8649755046240, 129746337080864, 1946195056159200, 29192926013193600, 437893890197853824, 6568408355529888210, 98526125332947516960, 1477891880032655307360
Offset: 0

Views

Author

Joerg Arndt, Jan 20 2013

Keywords

Comments

Set q=15 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].
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:
q=6: A221578, q=10: A221579, q=12: A221580,
q=14: A221581, q=15: A221582, q=18: A221583, q=20: A221584.

Programs

  • Maple
    with(numtheory):
    b:= proc(n) b(n):= add(phi(d)*15^(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, Feb 03 2013
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*15^(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)/(1-15*x^n)  );
    v=Vec(gf)

A221583 A sum over partitions (q=18), see first comment.

Original entry on oeis.org

1, 17, 323, 5814, 104958, 1889227, 34011900, 612213877, 11019954438, 198359179578, 3570467115834, 64268408079198, 1156831379431973, 20822964829665048, 374813367546080412, 6746640615829343087, 121439531095946141922, 2185911559727028566514
Offset: 0

Views

Author

Joerg Arndt, Jan 20 2013

Keywords

Comments

Set q=18 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].
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:
q=6: A221578, q=10: A221579, q=12: A221580,
q=14: A221581, q=15: A221582, q=18: A221583, q=20: A221584.

Programs

  • Maple
    with(numtheory):
    b:= proc(n) b(n):= add(phi(d)*18^(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, Feb 03 2013
  • Mathematica
    b[n_] := Sum[EulerPhi[d]*18^(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)/(1-18*x^n)  );
    v=Vec(gf)

A221584 A sum over partitions (q=20), see first comment.

Original entry on oeis.org

1, 19, 399, 7980, 159980, 3199581, 63999600, 1279991601, 25599991620, 511999832020, 10239999832020, 204799996632420, 4095999996640419, 81919999932640800, 1638399999932648400, 32767999998652808799, 655359999998652816380, 13107199999973052976380
Offset: 0

Views

Author

Joerg Arndt, Jan 20 2013

Keywords

Comments

Set q=20 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].
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:
q=6: A221578, q=10: A221579, q=12: A221580,
q=14: A221581, q=15: A221582, q=18: A221583, q=20: A221584.

Programs

  • PARI
    N=66; x='x+O('x^N);
    gf=prod(n=1,N, (1-x^n)/(1-20*x^n)  );
    v=Vec(gf)

A319753 Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of Product_{j>=1} (1 - x^j)/(1 - k*x^j).

Original entry on oeis.org

1, 1, -1, 1, 0, -1, 1, 1, 0, 0, 1, 2, 3, 0, 0, 1, 3, 8, 6, 0, 1, 1, 4, 15, 24, 14, 0, 0, 1, 5, 24, 60, 78, 27, 0, 1, 1, 6, 35, 120, 252, 232, 60, 0, 0, 1, 7, 48, 210, 620, 1005, 720, 117, 0, 0, 1, 8, 63, 336, 1290, 3096, 4080, 2152, 246, 0, 0, 1, 9, 80, 504, 2394, 7735, 15600, 16305, 6528, 490, 0, 0
Offset: 0

Views

Author

Ilya Gutkovskiy, Sep 27 2018

Keywords

Examples

			Square array begins:
   1,  1,   1,    1,     1,     1,  ...
  -1,  0,   1,    2,     3,     4,  ...
  -1,  0,   3,    8,    15,    24,  ...
   0,  0,   6,   24,    60,   120,  ...
   0,  0,  14,   78,   252,   620,  ...
   1,  0,  27,  232,  1005,  3096,  ...
		

Crossrefs

Programs

  • Mathematica
    Table[Function[k, SeriesCoefficient[Product[(1 - x^i)/(1 - k x^i), {i, n}], {x, 0, n}]][j - n], {j, 0, 11}, {n, 0, j}] // Flatten
    Table[Function[k, SeriesCoefficient[Exp[Sum[Sum[d (k^(i/d) - 1), {d, Divisors[i]}] x^i/i, {i, n}]], {x, 0, n}]][j - n], {j, 0, 11}, {n, 0, j}] // Flatten

Formula

G.f. of column k: Product_{j>=1} (1 - x^j)/(1 - k*x^j).
G.f. of column k: exp(Sum_{j>=1} ( Sum_{d|j} d*(k^(j/d) - 1) ) * x^j/j).
Previous Showing 11-18 of 18 results.