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A337574 a(n) is the dot product of the vectors of the first n primes and the next n primes. 2
6, 31, 112, 279, 652, 1231, 2140, 3363, 5132, 7647, 10600, 14583, 19754, 25435, 31894, 40617, 50866, 62583, 76174, 91431, 108124, 127319, 147868, 172493, 200392, 230281, 262140, 297413, 334756, 374607, 419958, 471113, 524892, 583853, 649458, 717339, 790760, 868997, 951672, 1039871, 1134792 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = Sum_{k=1..n} prime(k)*prime(n+k).

EXAMPLE

a(3) = 2*7 + 3*11 + 5*13 = 112.

MAPLE

P:= <seq(ithprime(i), i=1..500)>:

[seq(P[1..t]^%T . P[t+1..2*t], t=1..250)];

PROG

(PARI) a(n) = sum(k=1, n, prime(k)*prime(n+k)); \\ Michel Marcus, Sep 02 2020

CROSSREFS

Cf. A000040, A337573 (n such that a(n) is prime).

Cf. A033994 (similar when prime(n) is replaced with n).

Sequence in context: A024447 A303172 A143568 * A166786 A003728 A216370

Adjacent sequences:  A337571 A337572 A337573 * A337575 A337576 A337577

KEYWORD

nonn

AUTHOR

Robert Israel, Sep 01 2020

STATUS

approved

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Last modified November 25 10:26 EST 2020. Contains 338623 sequences. (Running on oeis4.)