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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

Table of n, a(n) for n=0..22.

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

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Last modified May 13 19:36 EDT 2021. Contains 343868 sequences. (Running on oeis4.)