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A110705 Numbers n such that "n 42's followed by 43" is prime. 2
0, 1, 2, 3, 4, 7, 17, 24, 59, 199, 743, 2558, 4896, 5539, 6192, 10977, 27679 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Equivalently, a(n) generates primes of the form (100^(1+a(n)) - 1) * 42/99 + 1. - Mohsen Hozan, Jan 23 2015

LINKS

Table of n, a(n) for n=1..17.

MATHEMATICA

t = 1; Do[ t = t*100 - 57; If[PrimeQ[t], Print[n]], {n, 0, 3000}]

robinsonQ[n_] := PrimeQ[(100^(1 + n) - 1) * 42/99 + 1]; Select[Range[200], robinsonQ] (* Robert G. Wilson v, Jan 23 2015 *)

PROG

(PARI) t=1; for(n=0, 10^6, t=100*t-57; if(ispseudoprime(t), print1(n, ", "))); \\ Joerg Arndt, Nov 21 2014

(PFGW) ABC2 1+(100^(1+$a)-1)*42/99

a: from 0 to 28000 \\ Charles R Greathouse IV, Mohsen Hozan, Jan 23 2015

CROSSREFS

Cf. A110704, A254002.

Sequence in context: A027362 A068194 A179985 * A139439 A119330 A084644

Adjacent sequences:  A110702 A110703 A110704 * A110706 A110707 A110708

KEYWORD

nonn,base,more

AUTHOR

Ray Chandler, Aug 04 2005

EXTENSIONS

a(13)-a(17) from Mohsen Hozan, Feb 10 2015

STATUS

approved

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Last modified May 31 02:51 EDT 2020. Contains 334747 sequences. (Running on oeis4.)