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A270890 Numbers n such that (8*10^n+49)/3 is prime. 496
0, 1, 2, 3, 4, 5, 6, 10, 24, 33, 34, 35, 45, 52, 56, 62, 65, 103, 166, 424, 886, 1418, 1825, 4895, 5715, 7011, 7810, 9097, 12773, 14746, 20085, 25359, 27967, 46629, 48507, 68722, 74944 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

For n>2, numbers such that the digit 2 followed by n-3 occurrences of the digit 6 followed by the digits 83 is prime (see Example section).

a(38) > 10^5.

LINKS

Table of n, a(n) for n=1..37.

Makoto Kamada, Search for 26w83.

EXAMPLE

3 is in this sequence because (8*10^3+49)/3 = 2683 is prime.

Initial terms and primes associated:

a(1) = 0, 19;

a(2) = 1, 43;

a(3) = 2, 283;

a(4) = 3, 2683;

a(5) = 4, 26683;

a(6) = 5, 266683, etc.

MATHEMATICA

Select[Range[0, 100000], PrimeQ[(8*10^#+49)/3] &]

PROG

(PARI) is(n)=isprime((8*10^n+49)/3) \\ Charles R Greathouse IV, Feb 16 2017

CROSSREFS

Cf. A056654, A268448, A269303, A270339, A270613, A270831.

Sequence in context: A271341 A306109 A281513 * A010350 A269858 A269848

Adjacent sequences:  A270887 A270888 A270889 * A270891 A270892 A270893

KEYWORD

nonn,more

AUTHOR

Robert Price, Mar 25 2016

STATUS

approved

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Last modified November 17 12:09 EST 2018. Contains 317276 sequences. (Running on oeis4.)