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A120819 Indices of primes in A057137. 11
171, 277, 367, 561, 567, 18881 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Digits are in ascending order beginning with 1 and after 9 comes 0.
Indices of primes in A057137.
All terms must end in 1 or 7: A057137(n) is even when n is even, and divisible by 3 iff n == 0, 2, 3, 5, 6, 8 or 9 (mod 10). - M. F. Hasler, Apr 14 2024
REFERENCES
Clifford A. Pickover, A Passion for Mathematics, Wiley, 2005; see p. 61, 298.
LINKS
EXAMPLE
a(1) = 12345678901234567890...01234567890...012345678901 = A057137(171) is the first prime term in A057137.
MATHEMATICA
fQ[n_] := PrimeQ@ FromDigits@ Mod[Range@n, 10]; lst = {}; Do[ If[fQ@n, AppendTo[lst, n]; Print@n], {n, 10000}]; lst
IntegerLength[Select[Table[FromDigits[PadRight[{}, n, {1, 2, 3, 4, 5, 6, 7, 8, 9, 0}]], {n, 1, 1001, 2}], PrimeQ]] (* Harvey P. Dale, Feb 07 2024 *)
PROG
(PARI) N=0; for(n=1, 600, if(ispseudoprime(N=10*N+n%10), print1(n", "))) \\ Charles R Greathouse IV, May 10 2014 (Comment: Surprisingly, this is faster than calling ispseudoprime() only when n ends in 1 or 7, even when much larger N's are considered, e.g., up to 3000. - M. F. Hasler, Apr 14 2024)
CROSSREFS
Sequence in context: A136365 A031900 A349097 * A115078 A183996 A062907
KEYWORD
base,hard,nonn,changed
AUTHOR
Robert G. Wilson v, Jul 05 2006
EXTENSIONS
18881 from Arjen K. Lenstra, Feb 20 2012
STATUS
approved

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Last modified April 20 09:04 EDT 2024. Contains 371799 sequences. (Running on oeis4.)