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.

A075765 a(n) = floor(prime(n)/n) + (prime(n) mod n).

Original entry on oeis.org

2, 2, 3, 4, 3, 3, 5, 5, 7, 11, 11, 4, 5, 4, 5, 8, 11, 10, 13, 14, 13, 16, 17, 20, 25, 26, 25, 26, 25, 26, 7, 7, 9, 7, 13, 11, 13, 15, 15, 17, 19, 17, 23, 21, 21, 19, 27, 35, 35, 33, 33, 35, 33, 39, 41, 43, 45, 43, 45, 45, 43, 49, 59, 59, 57, 57, 67, 69, 7, 73, 73, 75, 7, 8, 9, 8, 9, 12
Offset: 1

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Author

Werner D. Sand, Oct 09 2002

Keywords

Comments

The digital sum base n of the n-th prime. - Hieronymus Fischer, Dec 24 2007

Examples

			p(9)/9=23/9=2+5/9; a(9)=2+5=7
		

Crossrefs

Cf. A007953.

Programs

  • Mathematica
    fmQ[n_]:=Module[{pn=Prime[n]},Floor[pn/n]+Mod[pn,n]]
    fmQ/@Range[90]  (* Harvey P. Dale, Feb 25 2011 *)

Formula

p(n)/n = k + r; r
a(n) = ds_n(prime(n)), where ds_n = digital sum base n. - Hieronymus Fischer, Oct 09 2007
a(n) = prime(n) - (n-1)*sum_{k>0} floor(prime(n)/n^k) = prime(n) - (n-1)*floor(prime(n)/n). - Hieronymus Fischer, Oct 09 2007

Extensions

Corrected by Hieronymus Fischer, Oct 09 2007