OFFSET
1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..5000
FORMULA
MAPLE
A065091 := proc(n) ithprime(n+1) ; end proc:
A014076 := proc(n) if n = 1 then 1; else for a from procname(n-1)+2 by 2 do if not isprime(a) then return a ; end if; end do: end if; end proc:
A166160 := proc(n) (A065091(n)+A014076(n))/2-1 ; end proc: seq(A166160(n), n=1..120) ; # R. J. Mathar, May 21 2010
MATHEMATICA
A014076 := Select[Range@250, ! PrimeQ@# && OddQ@# &]; A166160 := Prime[Range[2, 150]]; Table[(A166160[[n]] + A014076[[n]])/2 - 1, {n, 1, 50}] (* G. C. Greubel, Sep 17 2017 *)
Module[{nn=250, op, onp}, op=Prime[Range[2, nn]]; onp=Select[Range[1, nn, 2], !PrimeQ[#]&]; Total[#]/2-1&/@Thread[{Take[op, Length[ onp]], onp}]] (* Harvey P. Dale, Mar 02 2025 *)
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
Juri-Stepan Gerasimov, Oct 09 2009
EXTENSIONS
Entries checked by R. J. Mathar, May 21 2010
STATUS
approved