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A355591
a(n) = (product of the first n odd primes) - (sum of the first n odd primes).
1
1, 0, 7, 90, 1129, 14976, 255199, 4849770, 111546337, 3234846488, 100280244907, 3710369067210, 152125131763369, 6541380665834736, 307444891294245379, 16294579238595021986, 961380175077106319097, 58644190679703485491136, 3929160775540133527938979
OFFSET
0,3
COMMENTS
The parity of a(n) is the opposite of the parity of n.
LINKS
FORMULA
a(n) = A070826(n+1) - A071148(n).
EXAMPLE
a(4) = (3*5*7*11) - (3+5+7+11) = 1129.
MAPLE
a:= n-> (l-> mul(i, i=l)-add(i, i=l))([ithprime(i)$i=2..n+1]):
seq(a(n), n=0..20); # Alois P. Heinz, Jul 12 2022
MATHEMATICA
FoldList[Times, 1, p = Prime[Range[2, 20]]] - Prepend[Accumulate[p], 0] (* Amiram Eldar, Jul 14 2022 *)
PROG
(Python)
from itertools import count, islice
from sympy import nextprime
def agen():
p, s, primen = 1, 0, 2
while True:
yield p - s; primen = nextprime(primen); p *= primen; s += primen
print(list(islice(agen(), 19))) # Michael S. Branicky, Jul 12 2022
(PARI) a(n) = my(vp=primes(n+1)); vecprod(vp)/2 - vecsum(vp) + 2; \\ Michel Marcus, Jul 12 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Des MacHale and Bernard Schott, Jul 12 2022
EXTENSIONS
More terms from Michael S. Branicky, Jul 12 2022
STATUS
approved