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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A286634 Numerator of the ratio of alternate consecutive prime gaps: Numerator ((prime(n + 3) - prime(n + 2))/(prime(n + 1) - prime(n))).

Original entry on oeis.org

2, 2, 1, 1, 1, 1, 3, 1, 1, 2, 1, 1, 3, 3, 1, 1, 2, 1, 3, 2, 1, 2, 2, 1, 1, 1, 1, 7, 1, 3, 1, 5, 1, 3, 3, 2, 1, 3, 1, 5, 1, 2, 1, 3, 6, 1, 1, 1, 3, 1, 5, 3, 3, 1, 1, 1, 2, 1, 5, 7, 2, 1, 1, 7, 3, 5, 1, 2, 3, 2, 1, 3, 2, 1, 2, 2, 1, 5, 1, 1, 1, 3, 2, 1, 2, 2, 1, 1, 6, 2, 1, 1, 1, 3, 3, 1, 3, 3, 5, 1
Offset: 1

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Author

Andres Cicuttin, May 11 2017

Keywords

Crossrefs

Cf. A285851 (denominators), A001223, A000040, A272863, A276309.

Programs

  • Mathematica
    Table[Numerator[(Prime[k+3]-Prime[k+2])/(Prime[k+1]-Prime[k])], {k, 100}]

Formula

a(n) = numerator((prime(n + 3) - prime(n + 2))/(prime(n + 1) - prime(n))).
A000040(n+3) = 5 + Sum_{k=1..n} ((1+(-1)^k)*Product_{j=1..k}(a(j)/A285851(j))^((1+(-1)^j)/2) + ((1-(-1)^k)/2)*Product_{j=1..k}(a(j)/A285851(j))^((1-(-1)^j)/2)), for n>0.
A001223(n+2) = (1+(-1)^n)*Product_{j=1..n}(a(j)/A285851(j))^((1+(-1)^j)/2) - ((-1+(-1)^n)/2)*Product_{j=1..n}(a(j)/A285851(j))^((1-(-1)^j)/2), for n>0
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