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.

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A305619 Expansion of e.g.f. log(1 + Sum_{k>=1} x^prime(k)/prime(k)).

Original entry on oeis.org

0, 1, 2, -3, 4, -10, 636, -1078, -18416, -131976, 5035920, 5333592, 187347744, -4079616528, -14669908512, -140154110640, 28743506893056, -92449999037568, 2738959517576448, -52969092379214976, 34211286306178560, -16812071564735736576, 1407763084021569335808
Offset: 1

Views

Author

Ilya Gutkovskiy, Jun 06 2018

Keywords

Examples

			E.g.f.: A(x) = x^2/2! + 2*x^3/3! - 3*x^4/4! + 4*x^5/5! - 10*x^6/6! + ...
exp(A(x)) = 1 + x^2/2 + x^3/3 + x^5/5 + x^7/7 + ... + x^A000040(k)/A000040(k) + ...
exp(exp(A(x))-1) = 1 + x^2/2! + 2*x^3/3! + 3*x^4/4! + 44*x^5/5! + ... + A218002(k)*x^k/k! + ...
		

Crossrefs

Programs

  • Maple
    a:=series(log(1+add(x^ithprime(k)/ithprime(k),k=1..100)),x=0,24): seq(n!*coeff(a,x,n),n=0..23); # Paolo P. Lava, Mar 26 2019
  • Mathematica
    nmax = 23; Rest[CoefficientList[Series[Log[1 + Sum[x^Prime[k]/Prime[k], {k, 1, nmax}]], {x, 0, nmax}], x] Range[0, nmax]!]
    a[n_] := a[n] = Boole[PrimeQ[n]] (n - 1)! - Sum[k Binomial[n, k] Boole[PrimeQ[n - k]] (n - k - 1)! a[k], {k, 1, n - 1}]/n; a[0] = 0; Table[a[n], {n, 23}]

A329261 Expansion of e.g.f. -log(1 - Sum_{k>=1} x^prime(k) / prime(k)!).

Original entry on oeis.org

0, 0, 1, 1, 3, 11, 40, 232, 1246, 8912, 65766, 561001, 5198424, 52513111, 577791292, 6806860347, 86303601008, 1163845620633, 16701819148776, 253608108810052, 4065574363467636, 68608467057149112, 1215544196988580438, 22564088376584800717
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 09 2019

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 23; CoefficientList[Series[-Log[1 - Sum[x^Prime[k]/Prime[k]!, {k, 1, nmax}]], {x, 0, nmax}], x] Range[0, nmax]!
    a[n_] := a[n] = Boole[PrimeQ[n]] + Sum[Binomial[n, k] Boole[PrimeQ[n - k]] k a[k], {k, 1, n - 1}]/n; a[0] = 0; Table[a[n], {n, 0, 23}]

Formula

a(0) = 0; a(n) = A010051(n) + (1/n) * Sum_{k=1..n-1} binomial(n,k) * A010051(n-k) * k * a(k).
Showing 1-2 of 2 results.