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A228593
Products of 2 successive primorials.
5
2, 12, 180, 6300, 485100, 69369300, 15330615300, 4951788741900, 2163931680210300, 1443342430700270100, 1297564845199542819900, 1488306877443875614425300, 2257761533082359307083180100, 3980433582824199458387646516300
OFFSET
1,1
COMMENTS
No sum of any number of terms is a perfect power.
LINKS
Wikipedia, Perfect power.
FORMULA
a(1) = 2; a(n) = 2*(Product_{i=1..n-1} A006094(i)), n >= 2.
a(n) = A002110(n-1)*A002110(n); n >= 1. - David James Sycamore, Jul 13 2023
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
STATUS
approved