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%I #24 Mar 21 2023 12:13:08
%S 5,25,32,352,365,6205,6224,143152,143181,4438611,4438648,181984568,
%T 181984611,8553276717,8553276770,504643329430,504643329491,
%U 33811103075897,33811103075968,2468210524545664,2468210524545743,204861473537296669,204861473537296758
%N Alternate adding and multiplying prime numbers: a(2n) = a(2n-1) * prime(2n+1) and a(2n-1) = a(2n) + prime(2n-2) for n >= 1.
%e a(1) = 2 + 3 = 5;
%e a(2) = 5 * 5 = 25;
%e a(3) = 25 + 7 = 32;
%e ...
%e a(40) = 2714410084880275101596278688487175846.
%o (Python)
%o from sympy import primerange
%o p = list(primerange(1, 200))
%o def a(n):
%o out = p[0] + p[1]
%o for i in range(1, n):
%o if i % 2:
%o out *= p[i + 1]
%o else:
%o out += p[i + 1]
%o return out
%o for n in range(1, 25):
%o print(a(n), end=", ")
%Y Cf. A047905, A047904, A077138, A222559, A332659, A332660.
%K nonn,easy
%O 1,1
%A _Adnan Baysal_, Feb 18 2020
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