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%I #20 Jul 11 2022 16:10:53
%S 1,0,1,20,193,2282,29989,510452,9699613,223092770,6469693101,
%T 200560489970,7420738134613,304250263526972,13082761331669749,
%U 614889782588491082,32589158477190044349,1922760350154212638630,117288381359406970982769,7858321551080267055878522
%N a(n) = (product of the first n primes) - (sum of the first n primes).
%C The parity of a(n) is the opposite of the parity of n.
%F a(n) = A002110(n) - A007504(n).
%e a(4) = (2*3*5*7) - (2+3+5+7) = 193.
%t FoldList[Times, 1, p = Prime[Range[20]]] - Prepend[Accumulate[p], 0] (* _Amiram Eldar_, Jul 08 2022 *)
%o (Python)
%o from itertools import count, islice
%o from sympy import nextprime
%o def agen():
%o p, s, primen = 1, 0, 0
%o while True:
%o yield p - s; primen = nextprime(primen); p *= primen; s += primen
%o print(list(islice(agen(), 20))) # _Michael S. Branicky_, Jul 08 2022
%o (PARI) a(n) = my(vp=primes(n)); vecprod(vp) - vecsum(vp); \\ _Michel Marcus_, Jul 08 2022
%Y Cf. A000040, A002110, A007504, A059841.
%K nonn
%O 0,4
%A _Des MacHale_ and _Bernard Schott_, Jul 08 2022