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A332659 Alternate multiplying and adding prime numbers: a(2n) = a(2n-1) + prime(2n+1) and a(2n-1) = a(2n) * prime(2n-2) for n >= 1.

%I A332659 #23 May 22 2020 04:03:39
%S A332659 6,11,77,88,1144,1161,22059,22082,640378,640409,23695133,23695174,
%T A332659 1018892482,1018892529,54001304037,54001304096,3294079549856,
%U A332659 3294079549923,233879648044533,233879648044606,18476492195523874,18476492195523957,1644407805401632173
%N A332659 Alternate multiplying and adding prime numbers: a(2n) = a(2n-1) + prime(2n+1) and a(2n-1) = a(2n) * prime(2n-2) for n >= 1.
%e A332659 a(1) =  2 * 3 =  6;
%e A332659 a(2) =  6 + 5 = 11;
%e A332659 a(3) = 11 * 7 = 77.
%o A332659 (Python)
%o A332659 from sympy import primerange
%o A332659 p = list(primerange(1, 1000))
%o A332659 def a(n):
%o A332659     out = p[0] * p[1]
%o A332659     for i in range(1, n):
%o A332659         if i % 2:
%o A332659             out += p[i + 1]
%o A332659         else:
%o A332659             out *= p[i + 1]
%o A332659     return out
%Y A332659 Cf. A047904, A047905, A077138, A222559, A332657, A332660.
%K A332659 nonn,easy
%O A332659 1,1
%A A332659 _Adnan Baysal_, Feb 18 2020