login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A073673 Rearrangement of natural numbers such that every partial product + 1 is a prime. 4
1, 2, 3, 5, 6, 9, 4, 7, 10, 17, 12, 11, 13, 8, 19, 27, 21, 26, 20, 16, 14, 28, 22, 18, 47, 30, 31, 23, 34, 37, 41, 45, 49, 33, 36, 58, 24, 62, 39, 56, 42, 93, 54, 25, 51, 53, 15, 70, 72, 73, 46, 50, 64, 97, 55, 57, 171, 96, 79, 81, 66, 71, 132, 89, 121, 29, 61, 60, 177, 32 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

From Robert G. Wilson v, Dec 24 2012: (Start)

Records: 1, 2, 3, 5, 6, 9, 10, 17, 19, 27, 28, 47, 49, 58, 62, 93, 97, 171, 177, 184, 221, 243, 470, 512, 573, 768, 856, 999, 1028, 1226, 1659, 2522, ...

Late Records: 1, 2, 3, 4, 7, 8, 14, 15, 29, 32, 35, 59, 75, ... (End)

LINKS

Robert G. Wilson v, Table of n, a(n) for n = 1..750

FORMULA

Conjecture: n/log(n) << a(n) << n*log(n). - Thomas Ordowski, Aug 09 2017

MATHEMATICA

f[s_List] := Block[{k = 1, p = Times @@ s}, While[ MemberQ[s, k] || !PrimeQ[k*p + 1], k++]; Append[s, k]]; Nest[f, {1}, 69] (* Robert G. Wilson v, Dec 24 2012 *)

PROG

(PARI) v=[1]; n=1; while(n<100, s=1+n*prod(i=1, #v, v[i]); if(isprime(s)&&!vecsearch(vecsort(v), n), v=concat(v, n); n=0); n++); v \\ Derek Orr, Jun 16 2015

CROSSREFS

Cf. A073674, A083769.

Sequence in context: A098211 A218013 A287876 * A179217 A118809 A121048

Adjacent sequences:  A073670 A073671 A073672 * A073674 A073675 A073676

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Aug 11 2002

EXTENSIONS

More terms from Sascha Kurz, Feb 01 2003

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 26 18:36 EDT 2019. Contains 321511 sequences. (Running on oeis4.)