A332660 -id:A332660 - cp's OEIS frontend

A332657 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.

5, 25, 32, 352, 365, 6205, 6224, 143152, 143181, 4438611, 4438648, 181984568, 181984611, 8553276717, 8553276770, 504643329430, 504643329491, 33811103075897, 33811103075968, 2468210524545664, 2468210524545743, 204861473537296669, 204861473537296758

Offset: 1

Adnan Baysal, Feb 18 2020

			a(1) = 2 + 3 = 5;
a(2) = 5 * 5 = 25;
a(3) = 25 + 7 = 32;
...
a(40) = 2714410084880275101596278688487175846.

Cf. A047905, A047904, A077138, A222559, A332659, A332660.

from sympy import primerange
p = list(primerange(1, 200))
def a(n):
    out = p[0] + p[1]
    for i in range(1, n):
        if i % 2:
            out *= p[i + 1]
        else:
            out += p[i + 1]
    return out
for n in range(1, 25):
    print(a(n), end=", ")

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.

Original entry on oeis.org

6, 11, 77, 88, 1144, 1161, 22059, 22082, 640378, 640409, 23695133, 23695174, 1018892482, 1018892529, 54001304037, 54001304096, 3294079549856, 3294079549923, 233879648044533, 233879648044606, 18476492195523874, 18476492195523957, 1644407805401632173

Offset: 1

Adnan Baysal, Feb 18 2020

			a(1) =  2 * 3 =  6;
a(2) =  6 + 5 = 11;
a(3) = 11 * 7 = 77.

Cf. A047904, A047905, A077138, A222559, A332657, A332660.

from sympy import primerange
p = list(primerange(1, 1000))
def a(n):
    out = p[0] * p[1]
    for i in range(1, n):
        if i % 2:
            out += p[i + 1]
        else:
            out *= p[i + 1]
    return out

cp's OEIS Frontend

A332657 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.

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