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 1-4 of 4 results.

A248821 Number of cubes that divide 1!*2!*3!*...*n!.

Original entry on oeis.org

1, 1, 1, 2, 6, 10, 36, 64, 220, 468, 1024, 2052, 7590, 16224, 50400, 142800, 246240, 510300, 2261952, 3545856, 14152320, 40986000, 68428800, 178293960, 784274400, 1526805504, 2782080000, 9307872000, 15858633600, 28225260000, 143730892800, 225167040000
Offset: 1

Views

Author

Clark Kimberling, Oct 15 2014

Keywords

Examples

			a(5) counts these cubes that divide 34560:  1^3, 2^3, 3^3, 4^3, 6^3, 12^3.
		

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; add(i[2]*x^numtheory[pi](i[1]),
          i=ifactors(n)[2])+`if`(n=1, 0, b(n-1))
        end:
    c:= proc(n) option remember; b(n)+`if`(n=1, 0, c(n-1)) end:
    a:= n->(p->mul(iquo(coeff(p, x, i), 3)+1, i=1..degree(p)))(c(n)):
    seq(a(n), n=1..30);  # Alois P. Heinz, Oct 16 2014
  • Mathematica
    z = 40; p[n_] := Product[k!, {k, 1, n}];
    f[n_] := f[n] = FactorInteger[p[n]];
    r[m_, x_] := r[m, x] = m*Floor[x/m]
    u[n_] := Table[f[n][[i, 1]], {i, 1, Length[f[n]]}];
    v[n_] := Table[f[n][[i, 2]], {i, 1, Length[f[n]]}];
    t[m_, n_] := Apply[Times, 1 + r[m, v[n]]/m]
    m = 3; Table[t[m, n], {n, 1, z}] (* A248821 *)

A248822 Number of integers k^4 that divide 1!*2!*3!*...*n!.

Original entry on oeis.org

1, 1, 1, 2, 3, 8, 10, 36, 64, 200, 432, 630, 1088, 4800, 7590, 32448, 47040, 114240, 164160, 835920, 1302840, 4804800, 7091712, 25243920, 39168000, 171555840, 320973840, 667447200, 1113944832, 3338108928, 5181926400, 19372953600, 31804416000, 132562944000
Offset: 1

Views

Author

Clark Kimberling, Oct 15 2014

Keywords

Examples

			a(6) counts these integers k^4 that divide 24883200:  1^4, 2^4, 4^4, 8^4, 6^4, 12^4, 24^4.
		

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; add(i[2]*x^numtheory[pi](i[1]),
          i=ifactors(n)[2])+`if`(n=1, 0, b(n-1))
        end:
    c:= proc(n) option remember; b(n)+`if`(n=1, 0, c(n-1)) end:
    a:= n->(p->mul(iquo(coeff(p, x, i), 4)+1, i=1..degree(p)))(c(n)):
    seq(a(n), n=1..30);  # Alois P. Heinz, Oct 16 2014
  • Mathematica
    z = 40; p[n_] := Product[k!, {k, 1, n}];
    f[n_] := f[n] = FactorInteger[p[n]];
    r[m_, x_] := r[m, x] = m*Floor[x/m]
    u[n_] := Table[f[n][[i, 1]], {i, 1, Length[f[n]]}];
    v[n_] := Table[f[n][[i, 2]], {i, 1, Length[f[n]]}];
    t[m_, n_] := Apply[Times, 1 + r[m, v[n]]/m]
    m = 4; Table[t[m, n], {n, 1, z}] (* A248822 *)

A248823 Number of integers k^5 that divide 1!*2!*3!*...*n!.

Original entry on oeis.org

1, 1, 1, 2, 2, 6, 8, 10, 42, 64, 200, 432, 588, 1024, 3888, 6300, 21120, 33696, 52080, 114240, 328320, 816480, 3326400, 4435200, 6469632, 20616960, 57153600, 145411200, 258003900, 320973840, 791513856, 1634592960, 6403719168, 9967104000, 34939296000
Offset: 1

Views

Author

Clark Kimberling, Oct 15 2014

Keywords

Examples

			a(6) counts these integers k^5 that divide 24883200:  1, 32, 1024, 7776, 32768, 248832, these being k^5 for k = 1, 2, 3, 4, 6, 12.
		

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; add(i[2]*x^numtheory[pi](i[1]),
          i=ifactors(n)[2])+`if`(n=1, 0, b(n-1))
        end:
    c:= proc(n) option remember; b(n)+`if`(n=1, 0, c(n-1)) end:
    a:= n->(p->mul(iquo(coeff(p, x, i), 5)+1, i=1..degree(p)))(c(n)):
    seq(a(n), n=1..30);  # Alois P. Heinz, Oct 16 2014
  • Mathematica
    z = 40; p[n_] := Product[k!, {k, 1, n}];
    f[n_] := f[n] = FactorInteger[p[n]];
    r[m_, x_] := r[m, x] = m*Floor[x/m]
    u[n_] := Table[f[n][[i, 1]], {i, 1, Length[f[n]]}];
    v[n_] := Table[f[n][[i, 2]], {i, 1, Length[f[n]]}];
    t[m_, n_] := Apply[Times, 1 + r[m, v[n]]/m]
    m = 5; Table[t[m, n], {n, 1, z}] (* A248823 *)

A248824 Number of integers k^6 that divide 1!*2!*3!*...*n!.

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 6, 8, 18, 42, 64, 200, 432, 546, 960, 3888, 6000, 15180, 29952, 38976, 67200, 285600, 393984, 1632960, 3175200, 4165392, 6105600, 38413440, 55339200, 114048000, 205632000, 280219500, 448156800, 2621445120, 3777725952, 12940849152
Offset: 1

Views

Author

Clark Kimberling, Oct 15 2014

Keywords

Examples

			a(7) counts these integers k^6 that divide 125411328000 = A000178(6):  1, 64, 729, 4096, 46656, 2985984, these being k^6 for k = 1, 2, 3, 4, 6, 12.
		

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; add(i[2]*x^numtheory[pi](i[1]),
          i=ifactors(n)[2])+`if`(n=1, 0, b(n-1))
        end:
    c:= proc(n) option remember; b(n)+`if`(n=1, 0, c(n-1)) end:
    a:= n->(p->mul(iquo(coeff(p, x, i), 6)+1, i=1..degree(p)))(c(n)):
    seq(a(n), n=1..30);  # Alois P. Heinz, Oct 16 2014
  • Mathematica
    z = 40; p[n_] := Product[k!, {k, 1, n}];
    f[n_] := f[n] = FactorInteger[p[n]];
    r[m_, x_] := r[m, x] = m*Floor[x/m]
    u[n_] := Table[f[n][[i, 1]], {i, 1, Length[f[n]]}];
    v[n_] := Table[f[n][[i, 2]], {i, 1, Length[f[n]]}];
    t[m_, n_] := Apply[Times, 1 + r[m, v[n]]/m]
    m = 6; Table[t[m, n], {n, 1, z}] (* A248824 *)
Showing 1-4 of 4 results.