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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A057777 a(n) is the smallest number such that a(n)+1 is a prime and the largest power of 2 which divides it is 2^n. 1
1, 2, 4, 40, 16, 96, 192, 640, 256, 7680, 13312, 18432, 12288, 40960, 114688, 163840, 65536, 1179648, 786432, 5767168, 7340032, 23068672, 104857600, 377487360, 754974720, 167772160, 469762048, 2013265920, 3489660928, 12348030976 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..29.

EXAMPLE

The 4th term is 40. It is divisible by 8,40+1=41 is prime. Smaller multiples of 8 are not suitable because e.g. albeit 8|16 and 16+1=17 is a prime, but the largest power of 2 which divides 16 is not 8, it is 16. So 16 is not the 3rd, it is the 4th term here.

CROSSREFS

A000040, A006093.

Sequence in context: A009834 A018992 A098625 * A139735 A184952 A098337

Adjacent sequences:  A057774 A057775 A057776 * A057778 A057779 A057780

KEYWORD

nonn

AUTHOR

Labos Elemer, Nov 02 2000

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Nov 03 2000

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 October 23 23:11 EDT 2019. Contains 328379 sequences. (Running on oeis4.)