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!)
A171253 Semi-sums (average) of any two distinct Mersenne primes (A000668). 5
5, 17, 19, 65, 67, 79, 4097, 4099, 4111, 4159, 65537, 65539, 65551, 65599, 69631, 262145, 262147, 262159, 262207, 266239, 327679, 1073741825, 1073741827, 1073741839, 1073741887, 1073745919, 1073807359, 1074003967 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Subsequence of A171252, excluding the terms of A000668 itself.
LINKS
FORMULA
a(n) = A171252(A014132(n)).
EXAMPLE
a(1) = (A000668(2)+A000668(1))/2, a(2) = (A000668(3)+A000668(1))/2, a(3) = (A000668(3)+A000668(2))/2, a(4) = (A000668(4)+A000668(1))/2, ,...
PROG
(PARI) concat(vector(#A000668, i, vector(i-1, j, A000668[i]+A000668[j])))/2 /* having defined A000668 as vector with initial terms of A000668 */
CROSSREFS
Cf. A171252 (includes terms of A000668), A171255 (primes in this sequence).
Sequence in context: A019401 A217079 A153320 * A226623 A171255 A304540
KEYWORD
nonn
AUTHOR
M. F. Hasler, Mar 06 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 11:45 EDT 2024. Contains 371278 sequences. (Running on oeis4.)