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.

A341980 Number of partitions of n into 9 distinct primes (counting 1 as a prime).

Original entry on oeis.org

1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 2, 0, 3, 0, 1, 0, 3, 0, 5, 0, 4, 1, 6, 0, 10, 0, 6, 1, 11, 1, 16, 1, 11, 2, 19, 2, 25, 1, 18, 5, 32, 4, 36, 2, 32, 9, 47, 7, 55, 7, 49, 14, 69, 10, 80, 12, 74, 22, 98, 19, 117, 22, 106, 34, 140, 31, 158, 32, 149, 54, 194, 48, 215, 50
Offset: 78

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, 10)
        end:
    a:= n-> coeff(b(n, numtheory[pi](n)), x, 9):
    seq(a(n), n=78..151);  # 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 - 1]]][
         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, 78, 151}] (* Jean-François Alcover, Feb 24 2022, after Alois P. Heinz *)

A341988 Number of ways to write n as an ordered sum of 9 primes (counting 1 as a prime).

Original entry on oeis.org

1, 9, 45, 156, 423, 954, 1887, 3384, 5661, 8935, 13446, 19332, 26838, 36126, 47691, 61668, 78696, 98631, 122665, 150516, 184230, 222438, 268146, 318564, 379383, 445572, 525942, 610344, 712872, 817290, 947166, 1075680, 1238148, 1391475, 1591236, 1773684, 2022241
Offset: 9

Views

Author

Ilya Gutkovskiy, Feb 24 2021

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 45; CoefficientList[Series[(x + Sum[x^Prime[k], {k, 1, nmax}])^9, {x, 0, nmax}], x] // Drop[#, 9] &

Formula

G.f.: ( x + Sum_{k>=1} x^prime(k) )^9.

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 1-3 of 3 results.