The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A212821 Smallest prime p of the form p = 3^n + k, where k has n prime divisors counted with multiplicity. 0
 2, 5, 13, 47, 97, 419, 953, 3019, 7457, 20963, 61609, 189947, 557041, 1614803, 4840313, 14430827, 43276097, 129959363, 388862281, 1165669339, 3493338001, 10471887539, 31395739673 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS EXAMPLE a(0) = 2 because 2 = 1 (A001222(1) = 0) + 3^0 = 1 + 1; a(1) = 5 because 5 = 2 (A001222(2) = 1) + 3^1 = 2 + 3; a(2) = 13 because 13 = 4 (A001222(4) = 2) + 3^2 = 4 + 9; a(3) = 47 because 47 = 20 (A001222(20) = 3) + 3^3 = 20 + 27; a(4) = 97 because 97 = 16 (A001222(16) = 4) + 3^4 = 16 + 81; a(5) = 419 because 419 = 176 (A001222(176) = 5) + 3^5 = 176 + 243. PROG (PARI) for(n=0, 30, p=3^n; k=1; while(1, if(bigomega(k)==n && isprime(p+k), print1(p+k, ", "); break, k++))) \\ Colin Barker, Jun 27 2014 CROSSREFS Cf. A001222. Sequence in context: A111563 A079573 A194635 * A067021 A269068 A098716 Adjacent sequences:  A212818 A212819 A212820 * A212822 A212823 A212824 KEYWORD nonn AUTHOR Juri-Stepan Gerasimov, Jul 02 2012 EXTENSIONS More terms from Colin Barker, Jun 27 2014 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 May 13 19:36 EDT 2021. Contains 343868 sequences. (Running on oeis4.)