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 A340468 a(n) is the least prime of the form 2 + Product_{i=n..m} prime(i). 1
 5, 7, 79, 13, 223, 19, 439, 130753887906569681111538991218568790437537693430279000532630035672131604633987039552816424896353327834998483765849409837393409377729040653460715050958787058270805333463, 31, 34826927179023475480751694965449235272424989980919 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS If n is in A029707, a(n) = 2+prime(n). If n is not in A029707 but prime(n) is in A051507, a(n) = 2+prime(n)*prime(n+1). a(15) > 10^1000 if it exists. LINKS Robert Israel, Table of n, a(n) for n = 2..14 EXAMPLE a(2) = 2+3 = 5. a(3) = 2+5 = 7. a(4) = 2+7*11 = 79. a(5) = 2+11 = 13. a(6) = 2+13*17 = 223. a(7) = 2+17 = 19. a(8) = 2+19*23 = 439. a(9) = 2+23*29*...*431. MAPLE f:= proc(n) local i, t; t:= 1; for i from n do t:= t*ithprime(i); if isprime(t+2) then return t+2 fi; od end proc: seq(f(n), n=2..14); PROG (Python) from sympy import isprime, nextprime, prime def a(n): prodpnpm = pm = prime(n) while not isprime(2+prodpnpm): pm = nextprime(pm); prodpnpm *= pm return 2+prodpnpm print([a(n) for n in range(2, 12)]) # Michael S. Branicky, Jan 08 2021 CROSSREFS Cf. A029707, A051507. Sequence in context: A107140 A141746 A067198 * A351636 A062583 A196139 Adjacent sequences: A340465 A340466 A340467 * A340469 A340470 A340471 KEYWORD nonn AUTHOR Robert Israel, Jan 08 2021 STATUS approved

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Last modified May 31 11:21 EDT 2023. Contains 363066 sequences. (Running on oeis4.)