OFFSET
1,1
COMMENTS
No sum of any number of terms is a perfect power.
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..196
Wikipedia, Perfect power.
FORMULA
a(1) = 2; a(n) = 2*(Product_{i=1..n-1} A006094(i)), n >= 2.
a(1) = 2, for n>1 a(n) = a(n-1)*prime(n-1)*prime(n). - David James Sycamore, Jul 15 2023
MATHEMATICA
nxt[{n_, a_}]:={n+1, a Prime[n]Prime[n+1]}; NestList[nxt, {1, 2}, 20][[All, 2]] (* Harvey P. Dale, Feb 19 2020 *)
PROG
(Magma) [n le 1 select 2 else Self(n-1)*NthPrime(n-1)*NthPrime(n): n in [1..14]]
(PARI) a(n) = vecprod(primes(n-1))*vecprod(primes(n)); \\ Michel Marcus, Aug 11 2023
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Arkadiusz Wesolowski, Aug 27 2013
STATUS
approved