A146215 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A146215

a(1) = 1, a(n+1) = a(n) + mod(a(n), p), where p is the lowest prime such that mod(a(n), p) is nonzero.

1, 2, 4, 5, 6, 7, 8, 10, 11, 12, 14, 16, 17, 18, 21, 22, 23, 24, 28, 29, 30, 32, 34, 35, 36, 37, 38, 40, 41, 42, 44, 46, 47, 48, 51, 52, 53, 54, 58, 59, 60, 64, 65, 66, 67, 68, 70, 71, 72, 74, 76, 77, 78, 81, 82, 83, 84, 88, 89, 90, 96, 97, 98, 100, 101, 102

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Former name: Addition of lowest nonzero prime division remainders.

The sequence is linear on a large scale. For 10^9 terms, a(n)/n is calculated to be 1.5859351, giving an approximate natural density of 0.6305428.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

MATHEMATICA

lp[n_]:=Module[{t=2}, While[Mod[n, t]==0, t=NextPrime[t]]; t]; NestList[ #+Mod[#, lp[#]]&, 1, 70] (* Harvey P. Dale, Jul 19 2013 *)

PROG

(MATLAB) % prime is expected to be an array containing all required primes.

a = zeros(1, terms); a(1) = 1; for n = 1:terms-1 j = 1; right = 0; while (right == 0) if (mod(a(n), prime(j)) == 0) j = j + 1; else right = 1; end end a(n+1) = a(n) + mod(a(n), prime(j)); end

CROSSREFS

Sequence in context: A249031 A085302 A193928 * A086743 A285432 A039079

Adjacent sequences: A146212 A146213 A146214 * A146216 A146217 A146218

KEYWORD

easy,nonn

AUTHOR

Sigurd Wenner (sigurd.wenner(AT)ils.uio.no), Oct 28 2008

EXTENSIONS

Corrected and extended by Harvey P. Dale, Jul 19 2013

STATUS

approved