

A183176


Numbers n such that (10^(2n+1)+12*10^n1)/3 is prime.


2



1, 3, 7, 11, 13, 17, 29, 31, 33, 77, 933, 1555, 11758
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OFFSET

1,2


COMMENTS

a(14) > 100,000.  Robert Price, Dec 29 2016


REFERENCES

C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 199697, pp. 19.


LINKS

Table of n, a(n) for n=1..13.
Patrick De Geest, World!Of Numbers, Palindromic Wing Primes (PWP's)
Makoto Kamada, Prime numbers of the form 33...33733...33
Index entries for primes involving repunits.


FORMULA

a(n) = (A077790(n)1)/2.


MATHEMATICA

Do[If[PrimeQ[(10^(2n + 1) + 12*10^n  1)/3], Print[n]], {n, 3000}]


PROG

(PARI) is(n)=ispseudoprime((10^(2*n+1)+12*10^n1)/3) \\ Charles R Greathouse IV, Jun 13 2017


CROSSREFS

Cf. A004023, A077775A077798, A107123A107127, A107648, A107649, A115073, A183174A183187.
Sequence in context: A020618 A184865 A055211 * A045417 A260379 A045418
Adjacent sequences: A183173 A183174 A183175 * A183177 A183178 A183179


KEYWORD

nonn,more,base


AUTHOR

Ray Chandler, Dec 28 2010


STATUS

approved



