login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A154273
Primes of the form: nonprime(prime(n)) + n.
1
2, 11, 79, 97, 109, 127, 151, 239, 313, 557, 599, 661, 719, 733, 797, 839, 1051, 1061, 1097, 1171, 1259, 1283, 1303, 1453, 1559, 1621, 1973, 1999, 2011, 2111, 2213, 2267, 2311, 2383, 2437, 2539, 2621, 2719, 2767, 2879, 2957, 3083, 3137, 3313, 3433, 3607
OFFSET
1,1
COMMENTS
Where n-th "prime nonprime"=A141468(A000040(n)) and 1st "prime nonprime" = 0.
EXAMPLE
For n=1, nonprime(prime(1))+1 = nonprime(2)+1 = 1+1 = 2 (prime), so a(1)=2.
For n=2, nonprime(prime(2))+2 = nonprime(3)+2 = 4+2 = 6 (composite).
For n=3, nonprime(prime(3))+3 = nonprime(5)+3 = 8+3 = 11 (prime), so a(2)=11, etc.
MAPLE
A154273 := proc(n) c := A141468(ithprime(n)) ; p := n+c ; if isprime(p) then printf("%d, ", p) ; end if; end proc: seq(A154273(n), n=1..700) ; # R. J. Mathar, May 01 2010
CROSSREFS
Sequence in context: A094569 A378670 A151418 * A253256 A163203 A142722
KEYWORD
nonn
AUTHOR
EXTENSIONS
Corrected (787 replaced by 797) and extended by R. J. Mathar, May 01 2010
STATUS
approved