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 A128490 Let p(k) denote the k-th prime. Sequence gives integers of the form [p(n+1)*p(n) - 1]/[p(n+1)-p(n)]. 1
 5, 7, 17, 19, 55, 71, 109, 111, 161, 191, 379, 415, 449, 505, 521, 681, 881, 961, 1025, 1079, 1189, 1231, 1639, 1799, 2071, 2449, 2591, 2755, 2991, 3079, 3457, 3499, 3921, 3951, 4159, 4265, 4815, 5161, 5201, 5831, 6049, 6425, 6805, 9281, 9505, 9521, 10751 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..47. EXAMPLE [5*3-1]/(5-2) = 14/2 = 7 [7*5-1]/(7-5) = 34/2 = 17 [11*7-1]/(11-7) = 76/4 = 19 MAPLE P:=proc(n) local i, j, k; for i from 1 by 1 to n do j:=(ithprime(i+1)*ithprime(i)-1)/(ithprime(i+1)-ithprime(i)); if j=trunc(j) then print(j); fi; od; end: P(1000); CROSSREFS Cf. A128491. Sequence in context: A075304 A168245 A242929 * A023519 A023517 A128491 Adjacent sequences: A128487 A128488 A128489 * A128491 A128492 A128493 KEYWORD easy,nonn AUTHOR Paolo P. Lava and Giorgio Balzarotti, Mar 05 2007 STATUS approved

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Last modified August 3 18:16 EDT 2024. Contains 374899 sequences. (Running on oeis4.)