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 A338543 Numbers k such that 1 + Product_{i
 1, 2, 8, 233, 431 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Numbers k such that A062347(k-1) == -1 (mod prime(k)). LINKS Mathematics StackExchange, Is 510511 the smallest euclid number e_n that divides by the next prime p. FORMULA a(n) = A081618(n)+1 for n >= 2. EXAMPLE a(3)=8 is a term because 1 + 2*3*5*7*11*13*17 = 510511 is divisible by prime(8)=19. MAPLE select(t -> 1+mul(ithprime(i), i=1..t-1) mod ithprime(t)=0, [\$1..1000]); PROG (PARI) isok(n) = ((1+vecprod(primes(n-1))) % prime(n)) == 0; \\ Michel Marcus, Nov 03 2020 CROSSREFS Cf. A002110, A006862, A081618, A062347, A341805. Sequence in context: A013344 A091503 A009588 * A125264 A028985 A067583 Adjacent sequences:  A338540 A338541 A338542 * A338544 A338545 A338546 KEYWORD nonn,more AUTHOR Robert Israel, Nov 01 2020 STATUS approved

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Last modified April 15 06:12 EDT 2021. Contains 342975 sequences. (Running on oeis4.)