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A095134 Sum of the product of the first floor(n/2) even-indexed primes and the product of the first floor(n/2) odd-indexed primes. 3
2, 5, 13, 31, 131, 383, 2143, 7057, 48197, 193433, 1483733, 6898961, 60231361, 293988703, 2808611363, 15253406999, 164272132459, 925319250199, 10930128162979, 65091314708809, 796351893424729, 5081275480436251 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..22.

FORMULA

Sum_{i=1..n} of the product_{j=2..n, 2} p_j (A066206) and the product_{k=1..n, 2} p_j (A066205).

EXAMPLE

a(5) = 2*5*11 + 3*7 = 131, a(6) = 2*5*11 + 3*7*13 = 383, a(7) =

2*5*11*17 + 3*7*13 = 2143, a(8) = 2*5*11*17 + 3*7*13*19 = 7057.

MATHEMATICA

f[n_] := Product[Prime[i], {i, 2, n, 2}] + Product[Prime[i], {i, 1, n, 2}]; f[1] = 2; Table[ f[n], {n, 22}]

CROSSREFS

Cf. A095137, A000040, A066206, A066205.

Sequence in context: A099515 A056367 A082733 * A086758 A179257 A116702

Adjacent sequences:  A095131 A095132 A095133 * A095135 A095136 A095137

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, May 27 2004

STATUS

approved

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Last modified November 14 01:24 EST 2019. Contains 329108 sequences. (Running on oeis4.)