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A007523 Primes in A092845 (decimal expansion of Pi written backwards).
(Formerly M2966)
4
3, 13, 51413, 951413, 2951413, 53562951413, 979853562951413 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Next term is probably A092845(711), a 712-digit probable prime (Baillie-Pomerance-Selfridge-Wagstaff test, cf. PARI/GP documentation) beginning 2116599102453... and ending ...62648323979853562951413.
a(8) = A092845(711) is now a proven prime. - Sean A. Irvine, Jan 07 2018
REFERENCES
M. Gardner, Whys and Wherefores, Univ. Chicago Press, 1989, p. 84.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
FORMULA
Equals A000040 intersect A092845.
EXAMPLE
51413 is in the list because it is prime and its decimal reversal, 31415, is the first 5 digits of Pi.
MATHEMATICA
Module[{nn=1000, rd}, d=RealDigits[Pi, 10, nn][[1]]; Select[Table[FromDigits[Reverse[Take[d, n]]], {n, nn}], PrimeQ]] (* Harvey P. Dale, Jul 11 2023 *)
CROSSREFS
Sequence in context: A320041 A016104 A112856 * A092830 A317481 A271393
KEYWORD
base,nonn
AUTHOR
EXTENSIONS
Edited by M. F. Hasler and N. J. A. Sloane, Mar 30 2008
Edited by T. D. Noe, Oct 30 2008
STATUS
approved

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Last modified March 18 21:02 EDT 2024. Contains 370951 sequences. (Running on oeis4.)