This site is supported by donations to The OEIS Foundation.

 Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS"). Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A181518 a(n) is the number for which 2^A181516(n)||(2*a(n))! 2
 2, 4, 7, 11, 13, 16, 22, 25, 28, 35, 37, 38, 41, 47, 50, 52, 56, 59, 64, 67, 70, 76, 88, 93, 97, 98, 100, 117, 122, 133, 137, 140, 143, 148, 158, 171, 176, 179, 182, 186, 193, 196, 200, 203, 213, 218, 223, 227, 233, 234, 236, 242, 247, 248, 253, 262, 280, 290, 299 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS MAPLE isA011371 := proc(n) option remember; local k, a; for k from 0 do a := A011371(k) ; if a > n then return false; elif a = n then return true; end if; end do: end proc: A181516 := proc(n) option remember; local a; if n = 1 then 3; else for a from procname(n-1)+1 do if isprime(a) then if isA011371(a) then return a; end if; end if; end do; end if; end proc: A181518 := proc(n) for m from 1 do if A011371(m) = A181516(n) then return m/2 ; end if; end do: end proc: # R. J. Mathar, Nov 04 2010 CROSSREFS Sequence in context: A229618 A087285 A107791 * A262231 A191323 A165288 Adjacent sequences:  A181515 A181516 A181517 * A181519 A181520 A181521 KEYWORD nonn,uned AUTHOR Vladimir Shevelev, Oct 26 2010 EXTENSIONS Corrected (88 inserted, 129 replaced by 179) and extended beyond 227 by R. J. Mathar, Nov 04 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
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 14 07:15 EST 2018. Contains 318090 sequences. (Running on oeis4.)