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 A178629 Numbers n such that A003418(n-1) = lcm(1,2,...,n-1) is congruent to 1 modulo n. 1
 2, 11, 29, 787, 15773 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS n must be prime. No further terms below 3.8*10^8. [Max Alekseyev, Jun 19 2011] LINKS EXAMPLE For the first nontrivial example: lcm(1,2,3,4,5,6,7,8,9,10) = 2520 and 2520 mod 11 = 1, so 11 is in the sequence. MATHEMATICA fQ[n_] := Mod[ LCM @@ Range[n - 1], n] == 1; k = 2; lst = {}; While[k < 10^6, If[ fQ@k, Print@k; AppendTo[lst, k]]; k++ ]; lst (* Robert G. Wilson v, Jun 02 2010 *) PROG (PARI) { L=1; for(n=2, 10^8, if( ispseudoprime(n), if(L%n==1, print(n)); L*=n); if( ispower(n, , &p) && ispseudoprime(p), L*=p );  ) } \\ Max Alekseyev, Jun 19 2011 CROSSREFS A158851(m-1) = 1 iff m = a(n), for some n. Sequence in context: A133558 A285812 A140745 * A062802 A103830 A162260 Adjacent sequences:  A178626 A178627 A178628 * A178630 A178631 A178632 KEYWORD nonn,more AUTHOR Nick Hobson (nickh(AT)qbyte.org), May 31 2010 STATUS approved

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Last modified February 19 00:54 EST 2020. Contains 332028 sequences. (Running on oeis4.)