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.

A353163 Expansion of e.g.f. exp(Sum_{p prime} x^p / (p-1)!).

Original entry on oeis.org

1, 0, 2, 3, 12, 65, 210, 1477, 7560, 45864, 338310, 2176031, 17657640, 139280869, 1150004856, 10572694860, 94834041120, 931995595457, 9384294360168, 96974005210273, 1066116104926500, 11838081891521760, 137785102884102366, 1652584041236345933
Offset: 0

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Author

Seiichi Manyama, Apr 28 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(sum(k=1, N, isprime(k)*x^k/(k-1)!))))
    
  • PARI
    a(n) = if(n==0, 1, sum(k=1, n, isprime(k)*k*binomial(n-1, k-1)*a(n-k)));

Formula

a(0) = 1; a(n) = Sum_{p<=n, p prime} p * binomial(n-1,p-1) * a(n-p).

A353164 Expansion of 1/(1 - Sum_{p prime} p * x^p).

Original entry on oeis.org

1, 0, 2, 3, 4, 17, 17, 63, 100, 211, 495, 846, 2057, 3831, 8181, 17078, 33788, 72705, 144801, 303452, 623115, 1274365, 2652052, 5408046, 11207927, 23020231, 47378495, 97774736, 200819019, 414365805, 852285510, 1755453858, 3616014678, 7441523271, 15332278869
Offset: 0

Views

Author

Seiichi Manyama, Apr 28 2022

Keywords

Crossrefs

Programs

  • PARI
    my(N=40, x='x+O('x^N)); Vec(1/(1-sum(k=1, N, isprime(k)*k*x^k)))
    
  • PARI
    a(n) = if(n==0, 1, sum(k=1, n, isprime(k)*k*a(n-k)));

Formula

a(0) = 1; a(n) = Sum_{p<=n, p prime} p * a(n-p).

A352914 Expansion of e.g.f. exp(Sum_{k>=1} prime(k)*x^k).

Original entry on oeis.org

1, 2, 10, 74, 676, 7592, 97024, 1416200, 23015248, 412777952, 8090869984, 171435904928, 3908548404160, 95264270043776, 2470715015425024, 67913132377486208, 1971038886452490496, 60212661838223997440, 1930529043247940342272, 64801071784954698480128
Offset: 0

Views

Author

Seiichi Manyama, Apr 28 2022

Keywords

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; `if`(n=0, 1, add(a(n-j)*
          ithprime(j)*j*binomial(n, j)*j!, j=1..n)/n)
        end:
    seq(a(n), n=0..20);  # Alois P. Heinz, Apr 28 2022
  • Mathematica
    a[0] = 1; a[n_] := a[n] = (n-1)! Sum[k Prime[k] a[n-k]/(n-k)!, {k, 1, n}];
    Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Dec 28 2022 *)
  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(sum(k=1, N, prime(k)*x^k))))
    
  • PARI
    a(n) = if(n==0, 1, (n-1)!*sum(k=1, n, k*prime(k)*a(n-k)/(n-k)!));

Formula

a(0) = 1; a(n) = (n-1)! * Sum_{k=1..n} A033286(k) * a(n-k)/(n-k)!.
Showing 1-3 of 3 results.