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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A177923 a(1)=19, a(2)=13, a(3)=37; thereafter a(n) = gpf(a(n-1)+a(n-2)+a(n-3)), where gpf = "greatest prime factor". 3
19, 13, 37, 23, 73, 19, 23, 23, 13, 59, 19, 13, 13, 5, 31, 7, 43, 3, 53, 11, 67, 131, 19, 31, 181, 11, 223, 83, 317, 89, 163, 569, 821, 1553, 109, 191, 109, 409, 709, 409, 509, 1627, 509, 23, 127, 659, 809, 29, 499, 191, 719, 1409, 773, 967, 67, 139, 23, 229, 23, 11, 263, 11, 19, 293, 19, 331, 643, 331, 29, 59, 419, 13, 491, 71, 23, 13, 107, 13, 19, 139, 19, 59, 31, 109, 199, 113, 421, 733, 181, 89, 59, 47, 13, 17, 11, 41, 23, 5, 23, 17, 5, 5, 3, 13, 7, 23, 43, 73, 139, 17, 229, 11, 257, 71, 113, 7, 191, 311, 509, 337 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

This is the periodic part of A177904 - it is periodic with period 212.

A smaller start is a(1)=3, a(2)=13, a(3)=7, but that would not produce the terms in the order of their first appearance in A177904.

There are several open questions concerning this class of sequences - see the Back-Caragiu reference in A177904.

LINKS

N. J. A. Sloane, Table of n, a(n) for n = 1..212

CROSSREFS

Cf. A006530, A177904, A175723.

Sequence in context: A196188 A089294 A088934 * A155848 A088399 A106706

Adjacent sequences:  A177920 A177921 A177922 * A177924 A177925 A177926

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 18 2010

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified October 20 15:14 EDT 2017. Contains 293612 sequences.