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.

A052467 Binomial transform of {b(n)}, where b(n)=1 for prime n and b(n)=0 otherwise.

Original entry on oeis.org

0, 1, 3, 6, 11, 20, 37, 70, 134, 255, 476, 869, 1564, 2821, 5201, 9948, 19793, 40562, 84271, 174952, 359576, 728805, 1457402, 2885051, 5681277, 11185110, 22103926, 43939533, 87864092, 176447165, 354929146, 713198803, 1428312446, 2846268351
Offset: 1

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Keywords

Comments

Number of compositions of n into a prime number of parts. - Vladeta Jovovic, Jan 31 2005
The number of pernicious numbers (A052294) between 2^(n-1) and 2^n. Although the graph looks almost like 2^n, the graph of a(n)/2^n has quite a bit of variation. - T. D. Noe, Mar 14 2009

Crossrefs

Programs

  • Mathematica
    b[n_] := Boole[ PrimeQ[n]]; a[n_] := Sum[ Binomial[n, k]*b[k], {k, 0, n}]; Table[a[n], {n, 0, 34}] // Differences (* Jean-François Alcover, Oct 25 2012 *)

Formula

G.f.: Sum_{k>=1} (x/(1 - x))^prime(k). - Ilya Gutkovskiy, Dec 28 2016
a(n) = A121497(n+1) - A121497(n). - Wesley Ivan Hurt, Jan 14 2022

Extensions

More terms from David Wasserman, Feb 25 2002
Description corrected by T. D. Noe, May 17 2003