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 11 results. Next

A341947 Number of partitions of n into 4 primes (counting 1 as a prime).

Original entry on oeis.org

1, 1, 2, 2, 4, 3, 5, 4, 6, 4, 7, 4, 9, 6, 10, 6, 12, 6, 14, 8, 15, 8, 18, 9, 21, 10, 20, 9, 23, 10, 26, 12, 27, 12, 31, 13, 34, 13, 33, 14, 39, 15, 42, 16, 43, 17, 48, 18, 53, 19, 52, 19, 58, 20, 61, 20, 61, 20, 68, 23, 73, 23, 73, 26, 82, 26, 84, 23, 84, 27, 92, 28, 98
Offset: 4

Views

Author

Ilya Gutkovskiy, Feb 24 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; series(`if`(n=0, 1,
         `if`(i<0, 0, (p-> `if`(p>n, 0, x*b(n-p, i)))(
         `if`(i=0, 1, ithprime(i)))+b(n, i-1))), x, 5)
        end:
    a:= n-> coeff(b(n, numtheory[pi](n)), x, 4):
    seq(a(n), n=4..76);  # Alois P. Heinz, Feb 24 2021
  • Mathematica
    b[n_, i_] := b[n, i] = Series[If[n == 0, 1,
         If[i < 0, 0, Function[p, If[p > n, 0, x*b[n - p, i]]][
         If[i == 0, 1, Prime[i]]] + b[n, i - 1]]], {x, 0, 5}];
    a[n_] := Coefficient[b[n, PrimePi[n]], x, 4];
    Table[a[n], {n, 4, 76}] (* Jean-François Alcover, Feb 15 2022, after Alois P. Heinz *)

A341948 Number of partitions of n into 5 primes (counting 1 as a prime).

Original entry on oeis.org

1, 1, 2, 2, 4, 4, 6, 5, 8, 6, 10, 7, 12, 9, 15, 10, 18, 12, 21, 14, 25, 15, 29, 18, 33, 21, 37, 20, 41, 23, 46, 26, 51, 27, 58, 31, 63, 34, 68, 33, 77, 39, 83, 42, 90, 43, 101, 48, 107, 53, 116, 52, 128, 58, 134, 61, 142, 61, 157, 68, 165, 73, 176, 73, 194, 82, 201, 84, 211
Offset: 5

Views

Author

Ilya Gutkovskiy, Feb 24 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; series(`if`(n=0, 1,
         `if`(i<0, 0, (p-> `if`(p>n, 0, x*b(n-p, i)))(
         `if`(i=0, 1, ithprime(i)))+b(n, i-1))), x, 6)
        end:
    a:= n-> coeff(b(n, numtheory[pi](n)), x, 5):
    seq(a(n), n=5..73);  # Alois P. Heinz, Feb 24 2021
  • Mathematica
    b[n_, i_] := b[n, i] = Series[If[n == 0, 1,
         If[i < 0, 0, Function[p, If[p > n, 0, x*b[n - p, i]]][
         If[i == 0, 1, Prime[i]]] + b[n, i - 1]]], {x, 0, 6}];
    a[n_] := Coefficient[b[n, PrimePi[n]], x, 5];
    Table[a[n], {n, 5, 73}] (* Jean-François Alcover, Feb 15 2022, after Alois P. Heinz *)

A341949 Number of partitions of n into 6 primes (counting 1 as a prime).

Original entry on oeis.org

1, 1, 2, 2, 4, 4, 7, 6, 9, 8, 12, 10, 16, 12, 19, 15, 24, 18, 29, 21, 35, 25, 41, 29, 49, 33, 56, 37, 63, 41, 72, 46, 82, 51, 91, 58, 105, 63, 115, 68, 128, 77, 143, 83, 158, 90, 174, 101, 193, 107, 211, 116, 231, 128, 250, 134, 273, 142, 294, 157, 321, 165, 347, 176, 374
Offset: 6

Views

Author

Ilya Gutkovskiy, Feb 24 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; series(`if`(n=0, 1,
         `if`(i<0, 0, (p-> `if`(p>n, 0, x*b(n-p, i)))(
         `if`(i=0, 1, ithprime(i)))+b(n, i-1))), x, 7)
        end:
    a:= n-> coeff(b(n, numtheory[pi](n)), x, 6):
    seq(a(n), n=6..70);  # Alois P. Heinz, Feb 24 2021
  • Mathematica
    b[n_, i_] := b[n, i] = Series[If[n == 0, 1,
         If[i < 0, 0, Function[p, If[p > n, 0, x*b[n - p, i]]][
         If[i == 0, 1, Prime[i]]] + b[n, i - 1]]], {x, 0, 7}];
    a[n_] := Coefficient[b[n, PrimePi[n]], x, 6];
    Table[a[n], {n, 6, 70}] (* Jean-François Alcover, Feb 15 2022, after Alois P. Heinz *)

A341950 Number of partitions of n into 7 primes (counting 1 as a prime).

Original entry on oeis.org

1, 1, 2, 2, 4, 4, 7, 7, 10, 9, 14, 12, 19, 16, 23, 19, 30, 24, 37, 29, 44, 35, 55, 41, 65, 49, 75, 56, 89, 63, 102, 72, 116, 82, 134, 91, 153, 105, 171, 115, 194, 128, 220, 143, 242, 158, 273, 174, 305, 193, 334, 211, 374, 231, 412, 250, 447, 273, 494, 294, 541, 321
Offset: 7

Views

Author

Ilya Gutkovskiy, Feb 24 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; series(`if`(n=0, 1,
         `if`(i<0, 0, (p-> `if`(p>n, 0, x*b(n-p, i)))(
         `if`(i=0, 1, ithprime(i)))+b(n, i-1))), x, 8)
        end:
    a:= n-> coeff(b(n, numtheory[pi](n)), x, 7):
    seq(a(n), n=7..68);  # Alois P. Heinz, Feb 24 2021
  • Mathematica
    b[n_, i_] := b[n, i] = Series[If[n == 0, 1,
         If[i < 0, 0, Function[p, If[p > n, 0, x*b[n - p, i]]][
         If[i == 0, 1, Prime[i]]] + b[n, i - 1]]], {x, 0, 8}];
    a[n_] := Coefficient[b[n, PrimePi[n]], x, 7];
    Table[a[n], {n, 7, 68}] (* Jean-François Alcover, Feb 15 2022, after Alois P. Heinz *)

A341946 Number of partitions of n into 3 primes (counting 1 as a prime).

Original entry on oeis.org

1, 1, 2, 2, 3, 2, 4, 2, 4, 2, 4, 2, 6, 3, 6, 2, 6, 3, 8, 3, 8, 3, 9, 4, 10, 3, 9, 2, 10, 4, 12, 3, 12, 4, 13, 4, 13, 3, 14, 3, 15, 5, 16, 4, 17, 4, 18, 6, 19, 4, 19, 3, 20, 6, 20, 3, 20, 4, 23, 7, 23, 4, 26, 5, 26, 6, 23, 3, 27, 5, 28, 7, 28, 6, 33, 5, 31, 7, 30, 5, 34
Offset: 3

Views

Author

Ilya Gutkovskiy, Feb 24 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; series(`if`(n=0, 1,
         `if`(i<0, 0, (p-> `if`(p>n, 0, x*b(n-p, i)))(
         `if`(i=0, 1, ithprime(i)))+b(n, i-1))), x, 4)
        end:
    a:= n-> coeff(b(n, numtheory[pi](n)), x, 3):
    seq(a(n), n=3..83);  # Alois P. Heinz, Feb 24 2021
  • Mathematica
    b[n_, i_] := b[n, i] = Series[If[n == 0, 1,
         If[i < 0, 0, Function[p, If[p > n, 0, x*b[n - p, i]]][
         If[i == 0, 1, Prime[i]]] + b[n, i-1]]], {x, 0, 4}];
    a[n_] := Coefficient[b[n, PrimePi[n]], x, 3];
    Table[a[n], {n, 3, 83}] (* Jean-François Alcover, Feb 14 2022, after Alois P. Heinz *)

A341951 Number of partitions of n into 8 primes (counting 1 as a prime).

Original entry on oeis.org

1, 1, 2, 2, 4, 4, 7, 7, 11, 10, 15, 14, 21, 19, 27, 23, 35, 30, 44, 37, 54, 44, 67, 55, 81, 65, 96, 75, 115, 89, 133, 102, 155, 116, 180, 134, 206, 153, 236, 171, 271, 194, 305, 220, 346, 242, 391, 273, 438, 305, 489, 334, 551, 374, 608, 412, 674, 447, 750, 494, 823
Offset: 8

Views

Author

Ilya Gutkovskiy, Feb 24 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; series(`if`(n=0, 1,
         `if`(i<0, 0, (p-> `if`(p>n, 0, x*b(n-p, i)))(
         `if`(i=0, 1, ithprime(i)))+b(n, i-1))), x, 9)
        end:
    a:= n-> coeff(b(n, numtheory[pi](n)), x, 8):
    seq(a(n), n=8..68);  # Alois P. Heinz, Feb 24 2021
  • Mathematica
    b[n_, i_] := b[n, i] = Series[If[n == 0, 1,
         If[i < 0, 0, Function[p, If[p > n, 0, x*b[n - p, i]]][
         If[i == 0, 1, Prime[i]]] + b[n, i - 1]]], {x, 0, 9}];
    a[n_] := Coefficient[b[n, PrimePi[n]], x, 8];
    Table[a[n], {n, 8, 68}] (* Jean-François Alcover, Feb 15 2022, after Alois P. Heinz *)

A341973 Number of partitions of n into 2 distinct primes (counting 1 as a prime).

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 0, 2, 1, 2, 1, 2, 0, 3, 1, 3, 1, 2, 0, 4, 1, 2, 0, 2, 0, 4, 1, 3, 1, 3, 0, 4, 0, 2, 1, 3, 0, 5, 1, 4, 1, 3, 0, 6, 1, 4, 0, 3, 0, 6, 1, 3, 0, 3, 0, 7, 1, 3, 1, 5, 0, 6, 0, 3, 1, 5, 0, 7, 1, 5, 1, 5, 0, 7, 0, 5, 1, 4, 0, 9, 1, 4, 0, 4, 0, 10, 1, 4, 0, 4, 0, 7
Offset: 3

Views

Author

Ilya Gutkovskiy, Feb 24 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; series(`if`(n=0, 1,
         `if`(i<0, 0, (p-> `if`(p>n, 0, x*b(n-p, i-1)))(
         `if`(i=0, 1, ithprime(i)))+b(n, i-1))), x, 3)
        end:
    a:= n-> coeff(b(n, numtheory[pi](n)), x, 2):
    seq(a(n), n=3..96);  # Alois P. Heinz, Feb 24 2021
  • Mathematica
    a[n_] := Select[IntegerPartitions[n, {2}, Join[{1},
        Prime[Range[PrimePi[n-1]]]]], #[[1]] != #[[2]]&] // Length;
    a /@ Range[3, 100] (* Jean-François Alcover, Jul 13 2021 *)

Formula

a(n) = A117929(n) + A010051(n-1). - R. J. Mathar, Oct 01 2021

A341982 Number of ways to write n as an ordered sum of 2 primes (counting 1 as a prime).

Original entry on oeis.org

1, 2, 3, 2, 3, 2, 4, 2, 3, 0, 4, 2, 5, 2, 4, 0, 6, 2, 6, 2, 5, 0, 8, 2, 5, 0, 4, 0, 8, 2, 6, 2, 7, 0, 8, 0, 5, 2, 6, 0, 10, 2, 8, 2, 7, 0, 12, 2, 8, 0, 6, 0, 12, 2, 6, 0, 7, 0, 14, 2, 7, 2, 10, 0, 12, 0, 6, 2, 10, 0, 14, 2, 11, 2, 10, 0, 14, 0, 10, 2, 9, 0, 18, 2, 9, 0, 8
Offset: 2

Views

Author

Ilya Gutkovskiy, Feb 24 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember; series(`if`(n=0, 1, x*add(
          `if`(j=1 or isprime(j), b(n-j), 0), j=1..n)), x, 3)
        end:
    a:= n-> coeff(b(n), x, 2):
    seq(a(n), n=2..88);  # Alois P. Heinz, Feb 24 2021
  • Mathematica
    nmax = 88; CoefficientList[Series[(x + Sum[x^Prime[k], {k, 1, nmax}])^2, {x, 0, nmax}], x] // Drop[#, 2] &

Formula

G.f.: ( x + Sum_{k>=1} x^prime(k) )^2.

A341719 Number of partitions of n into 9 primes (counting 1 as a prime).

Original entry on oeis.org

1, 1, 2, 2, 4, 4, 7, 7, 11, 11, 16, 15, 23, 21, 30, 27, 39, 35, 51, 44, 63, 54, 78, 67, 97, 81, 116, 96, 139, 115, 166, 133, 194, 155, 227, 180, 265, 206, 305, 236, 351, 271, 403, 305, 460, 346, 522, 391, 592, 438, 668, 489, 751, 551, 844, 608, 942, 674, 1050, 750
Offset: 9

Views

Author

Ilya Gutkovskiy, Feb 24 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; series(`if`(n=0, 1,
         `if`(i<0, 0, (p-> `if`(p>n, 0, x*b(n-p, i)))(
         `if`(i=0, 1, ithprime(i)))+b(n, i-1))), x, 10)
        end:
    a:= n-> coeff(b(n, numtheory[pi](n)), x, 9):
    seq(a(n), n=9..68);  # Alois P. Heinz, Feb 24 2021
  • Mathematica
    b[n_, i_] := b[n, i] = Series[If[n == 0, 1,
         If[i < 0, 0, Function[p, If[p > n, 0, x*b[n - p, i]]][
         If[i == 0, 1, Prime[i]]] + b[n, i - 1]]], {x, 0, 10}];
    a[n_] := Coefficient[b[n, PrimePi[n]], x, 9];
    Table[a[n], {n, 9, 68}] (* Jean-François Alcover, Feb 26 2022, after Alois P. Heinz *)

A341972 Number of partitions of n into 10 primes (counting 1 as a prime).

Original entry on oeis.org

1, 1, 2, 2, 4, 4, 7, 7, 11, 11, 17, 16, 24, 23, 32, 30, 43, 39, 56, 51, 71, 63, 89, 78, 111, 97, 134, 116, 164, 139, 197, 166, 232, 194, 275, 227, 324, 265, 374, 305, 438, 351, 505, 403, 578, 460, 665, 522, 760, 592, 859, 668, 978, 751, 1105, 844, 1239, 942, 1394
Offset: 10

Views

Author

Ilya Gutkovskiy, Feb 24 2021

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; series(`if`(n=0, 1,
         `if`(i<0, 0, (p-> `if`(p>n, 0, x*b(n-p, i)))(
         `if`(i=0, 1, ithprime(i)))+b(n, i-1))), x, 11)
        end:
    a:= n-> coeff(b(n, numtheory[pi](n)), x, 10):
    seq(a(n), n=10..68);  # Alois P. Heinz, Feb 24 2021
  • Mathematica
    b[n_, i_] := b[n, i] = Series[If[n == 0, 1,
         If[i < 0, 0, Function[p, If[p > n, 0, x*b[n - p, i]]][
         If[i == 0, 1, Prime[i]]] + b[n, i - 1]]], {x, 0, 11}];
    a[n_] := Coefficient[b[n, PrimePi[n]], x, 10];
    Table[a[n], {n, 10, 68}] (* Jean-François Alcover, Feb 26 2022, after Alois P. Heinz *)
Showing 1-10 of 11 results. Next