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A140319 Exponential primorial: a(n)=prime(n)^a(n-1), a(0)=1, where prime(n)=A000040(n). 4
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.

J. Sondow, "Exponential Factorial."

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.

Cf. A152859 (alternate definition: start with a(0)=0), A167155. [M. F. Hasler, Nov 03 2009]

Sequence in context: A049384 A132859 A103562 * 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, added initial term a(0)=1 M. F. Hasler, Nov 03 2009

STATUS

approved

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Last modified March 30 20:18 EDT 2017. Contains 284302 sequences.