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 A140319 Exponential primorial: a(n)=prime(n)^a(n-1), a(0)=1, where prime(n)=A000040(n). 7
 1, 2, 9, 1953125 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The next term is too large to include. LINKS Table of n, a(n) for n=0..3. Jonathan Sondow, Exponential Factorial, Eric Weisstein's World of Mathematics. FORMULA Sum_{n>=0} 1/a(n) = A167155. - Amiram Eldar, Nov 15 2020 EXAMPLE a(1) = prime(1)^a(0) = 2^1 = 2. a(2) = 3^2 = 9. a(3) = 5^9 = 1953125. a(4) = 7^1953125 has 1650583 digits, starting with 12864794... and ending in ...31920807. [M. F. Hasler, Nov 03 2009] MAPLE P:=proc(n) local a, i; a:=2; print(a); for i from 2 by 1 to n do a:=ithprime(i)^a; print(a); od; end: P(5); PROG (PARI) A140319(n)=if(n, prime(n)^A140319(n-1), 1) \\ M. F. Hasler, Nov 03 2009 CROSSREFS Cf. A002110, A049384, A139802, A167155. Cf. A152859 (alternate definition: start with a(0)=0), A167155. [M. F. Hasler, Nov 03 2009] Sequence in context: A132859 A103562 A309861 * A120314 A050924 A181500 Adjacent sequences: A140316 A140317 A140318 * A140320 A140321 A140322 KEYWORD easy,nonn AUTHOR Paolo P. Lava and Giorgio Balzarotti, May 26 2008 EXTENSIONS Corrected offset/definition, and initial a(0)=1 from M. F. Hasler, Nov 03 2009 STATUS approved

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Last modified June 9 13:49 EDT 2023. Contains 363180 sequences. (Running on oeis4.)