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 1-3 of 3 results.

A339109 Number of compositions (ordered partitions) of n into distinct parts >= 8.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 5, 5, 7, 7, 9, 9, 11, 11, 19, 19, 27, 33, 41, 47, 61, 67, 81, 93, 107, 143, 163, 199, 243, 309, 353, 443, 517, 631, 729, 873, 995, 1307, 1459, 1795, 2115, 2625, 3089, 3767, 4405, 5371, 6297, 7557, 8771, 10463, 12811, 14911
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 23 2020

Keywords

Examples

			a(17) = 3 because we have [17], [9, 8] and [8, 9].

Links

Crossrefs

Cf. A017902, A025153, A032020, A032022, A185328, A339101, A339102, A339103, A339104, A339108, A339110.

Programs

  • Maple
    b:= proc(n, i, p) option remember;
      `if`(n=0, p!, `if`((i-7)*(i+8)/2 b(n$2, 0):
seq(a(n), n=0..64);  # Alois P. Heinz, Nov 23 2020
  • Mathematica
    nmax = 64; CoefficientList[Series[Sum[k! x^(k (k + 15)/2)/Product[1 - x^j, {j, 1, k}], {k, 0, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Sum_{k>=0} k! * x^(k*(k + 15)/2) / Product_{j=1..k} (1 - x^j).

A339110 Number of compositions (ordered partitions) of n into distinct parts >= 9.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 5, 5, 7, 7, 9, 9, 11, 11, 13, 19, 21, 27, 35, 41, 49, 61, 69, 81, 95, 107, 121, 163, 177, 219, 263, 329, 373, 469, 537, 657, 755, 899, 1021, 1219, 1485, 1707, 2027, 2417, 2881, 3445, 4077, 4809, 5735, 6755, 7969, 9307
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 23 2020

Keywords

Examples

			a(19) = 3 because we have [19], [10, 9] and [9, 10].

Links

Crossrefs

Cf. A017903, A025154, A032020, A032022, A185329, A339101, A339102, A339103, A339104, A339108, A339109.

Programs

  • Maple
    b:= proc(n, i, p) option remember;
      `if`(n=0, p!, `if`((i-8)*(i+9)/2 b(n$2, 0):
seq(a(n), n=0..69);  # Alois P. Heinz, Nov 23 2020
  • Mathematica
    nmax = 66; CoefficientList[Series[Sum[k! x^(k (k + 17)/2)/Product[1 - x^j, {j, 1, k}], {k, 0, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Sum_{k>=0} k! * x^(k*(k + 17)/2) / Product_{j=1..k} (1 - x^j).

A339170 Number of compositions (ordered partitions) of n into distinct parts, the least being 7.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 8, 8, 14, 14, 20, 20, 26, 26, 32, 32, 62, 62, 92, 116, 146, 170, 224, 248, 302, 350, 404, 572, 650, 818, 1016, 1328, 1526, 1958, 2300, 2852, 3314, 4010, 4592, 6248, 6974, 8750, 10436, 13196, 15722, 19442, 22952
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 25 2020

Keywords

Examples

			a(24) = 8 because we have [17, 7], [9, 8, 7], [9, 7, 8], [8, 9, 7], [8, 7, 9], [7, 17], [7, 9, 8] and [7, 8, 9].

Links

Crossrefs

Cf. A026800, A026828, A339108, A339162, A339163, A339164, A339165, A339166, A339169, A339171, A339172.

Programs

  • Mathematica
    nmax = 64; CoefficientList[Series[Sum[k! x^(k (k + 13)/2)/Product[1 - x^j, {j, 1, k - 1}], {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Sum_{k>=1} k! * x^(k*(k + 13)/2) / Product_{j=1..k-1} (1 - x^j).
Showing 1-3 of 3 results.

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