A337574 a(n) is the dot product of the vectors of the first n primes and the next n primes.
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
Offset: 1
Keywords
Examples
a(3) = 2*7 + 3*11 + 5*13 = 112.
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Crossrefs
Programs
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Maple
P:=
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Mathematica
Table[Prime[Range[n]].Prime[Range[n+1,2n]],{n,50}] (* Harvey P. Dale, Mar 30 2024 *) -
PARI
a(n) = sum(k=1, n, prime(k)*prime(n+k)); \\ Michel Marcus, Sep 02 2020
Formula
a(n) = Sum_{k=1..n} prime(k)*prime(n+k).