login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A190197 a(1) = 2. For n > 1, a(n) is the least prime > a(n-1)*n/2. 0
2, 3, 5, 11, 29, 89, 313, 1259, 5669, 28349, 155921, 935531, 6080957, 42566731, 319250501, 2554004029, 21709034261, 195381308371, 1856122429537, 18561224295377, 194892855101467, 2143821406116139, 24653946170335607, 295847354044027363, 3698091925550342059, 48075195032154446803 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..26.

MATHEMATICA

nxt[{n_, a_}]:={n+1, NextPrime[a (n+1)/2]}; NestList[nxt, {1, 2}, 30][[All, 2]] (* Harvey P. Dale, Feb 05 2020 *)

PROG

(PARI) lista(nn) = {my(a=2); print1(a, ", "); for (n=2, nn, if (a*n % 2, a = nextprime(a*n/2), a = nextprime(a*n/2+1)); print1(a, ", "); ); } \\ Michel Marcus, Sep 15 2019

CROSSREFS

Sequence in context: A047934 A090235 A265418 * A173631 A182987 A334814

Adjacent sequences:  A190194 A190195 A190196 * A190198 A190199 A190200

KEYWORD

nonn

AUTHOR

Pierre CAMI, May 08 2011

EXTENSIONS

More terms from Michel Marcus, Sep 15 2019

Name edited by Felix Fröhlich, Sep 15 2019

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 June 14 10:04 EDT 2021. Contains 345025 sequences. (Running on oeis4.)