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 A048756 Prime repunits in ascending prime bases (written in decimal). 0
 3, 13, 305175781 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 2^2-1=3 is prime; (3^3-1)/2=13 is prime; (5^13-1)/4=305175781 is prime; the next term is too gigantic to be computed simply. LINKS FORMULA a(p)=((p^a(p-1))-1)/(p-1); a(p)=111...111 in base p with a(p-1) 1's; p runs though the primes. CROSSREFS Sequence in context: A317481 A271393 A087345 * A174211 A264611 A157323 Adjacent sequences:  A048753 A048754 A048755 * A048757 A048758 A048759 KEYWORD nonn,bref AUTHOR Xavier Labouze (Xavier.Labouze(AT)cep.u-psud.fr) STATUS approved

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Last modified January 22 11:52 EST 2019. Contains 319363 sequences. (Running on oeis4.)