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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A068698 Smallest primes in the reverse concatenation of n consecutive odd numbers. 0
 3, 31, 0, 59575553, 15131197, 0, 55535149474543, 6361595755535149, 0, 1151131111091071051031019997, 207205203201199197195193191189187, 0, 65636159575553514947454341, 4543413937353331292725232119, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..15. EXAMPLE a(5) = 15131197 is a prime and a concatenation of 15,13,11,9 and 7. MAPLE for n from 1 to 32 do d := 0:c := true: if((n mod 3)=0) then c := false:a := 0:end if: while(c=true) do a := 2*(n+d)-1:for j from 1 to n-1 do a := 2*(n+d-j)-1+10^( floor(evalf(log(2*(n+d-j)-1)/log(10))+0.0000000001 )+1)*a:end do: if(isprime(a))then c := false:end if:d := d+1:end do:b[n] := a:end do:seq(b[h], h=1..32); CROSSREFS Sequence in context: A155731 A145385 A059232 * A053300 A322777 A089281 Adjacent sequences: A068695 A068696 A068697 * A068699 A068700 A068701 KEYWORD base,hard,nonn AUTHOR Amarnath Murthy, Mar 04 2002 EXTENSIONS More terms from Sascha Kurz, Mar 27 2002 Definition clarified by Harvey P. Dale, Dec 25 2022 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.

Last modified July 13 18:54 EDT 2024. Contains 374285 sequences. (Running on oeis4.)