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

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A071216 a(n) is the largest prime factor of prime(n) + prime(n+1). 8
5, 2, 3, 3, 3, 5, 3, 7, 13, 5, 17, 13, 7, 5, 5, 7, 5, 2, 23, 3, 19, 3, 43, 31, 11, 17, 7, 3, 37, 5, 43, 67, 23, 3, 5, 11, 5, 11, 17, 11, 5, 31, 3, 13, 11, 41, 31, 5, 19, 11, 59, 5, 41, 127, 13, 19, 5, 137, 31, 47, 3, 5, 103, 13, 7, 3, 167, 19, 29, 13, 89, 11, 37, 47, 127, 193, 131, 19 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

a(n) = A006530(A001043(n)).

MATHEMATICA

pf[x_] := Part[Reverse[Flatten[FactorInteger[x]]], 2]; Table[pf[Prime[w+1]+Prime[w]], {w, 1, 128}]

PROG

(PARI) a(n) = vecmax(factor(prime(n)+prime(n+1))[, 1]); \\ Michel Marcus, Aug 29 2019

CROSSREFS

Cf. A006530, A001043, A071215.

Sequence in context: A059650 A112244 A210487 * A069483 A011226 A019812

Adjacent sequences:  A071213 A071214 A071215 * A071217 A071218 A071219

KEYWORD

easy,nonn

AUTHOR

Labos Elemer, May 17 2002

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 25 14:51 EDT 2022. Contains 354071 sequences. (Running on oeis4.)