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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A286567 Smallest prime factor of the n-th Jacobsthal number: a(n) = A020639(A001045(n)), with a(1)=a(2)=1. 3
1, 1, 3, 5, 11, 3, 43, 5, 3, 11, 683, 3, 2731, 43, 3, 5, 43691, 3, 174763, 5, 3, 23, 2796203, 3, 11, 2731, 3, 5, 59, 3, 715827883, 5, 3, 43691, 11, 3, 1777, 174763, 3, 5, 83, 3, 2932031007403, 5, 3, 47, 283, 3, 43, 11, 3, 5, 107, 3, 11, 5, 3, 59, 2833, 3, 768614336404564651, 715827883, 3, 5, 11, 3, 7327657, 5, 3, 11, 56409643, 3, 1753, 223, 3, 5, 43, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Hans Havermann, Table of n, a(n) for n = 1..1122

FORMULA

a(n) = A020639(A001045(n)).

MATHEMATICA

Rest[FactorInteger[#][[1, 1]]&/@LinearRecurrence[{1, 2}, {0, 1}, 100]] (* Harvey P. Dale, Sep 23 2018 *)

PROG

(Scheme) (define (A286567 n) (A020639 (A001045 n)))

CROSSREFS

Cf. A001045, A020639, A278165.

Sequence in context: A297422 A064523 A268034 * A258862 A139430 A143386

Adjacent sequences:  A286564 A286565 A286566 * A286568 A286569 A286570

KEYWORD

nonn

AUTHOR

Antti Karttunen & Hans Havermann, May 21 2017

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 July 15 14:33 EDT 2019. Contains 325031 sequences. (Running on oeis4.)