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A340861 a(n) is the least prime of the form Sum_{1<=i<=2*n-1} prime(i+1)*prime(i+k) 1
83, 373, 1543, 2393, 4723, 13997, 18047, 38039, 43777, 62801, 56383, 95803, 109433, 122701, 173687, 268973, 250949, 359441, 363619, 430589, 832331, 813797, 932749, 925273, 1052719, 1356499, 1235821, 1466519, 1598507, 1644497, 1789391, 1987849, 3401831, 3079553, 2706679, 3551921, 3571741, 5041723 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Robert Israel, Table of n, a(n) for n = 2..10000

EXAMPLE

a(2) = 3*3+5*5+7*7 = 83 is prime.

a(3) = 3*3+5*5+7*7+11*11+13*13 = 373 is prime.

a(4) = 3*7+5*11+7*13+11*17+13*19+17*23+19*29 = 1543 is prime.

MAPLE

f:= proc(n) local B, C, i, k, t;

  B:= [seq(ithprime(i), i=2..2*n)];

  C:= [seq(ithprime(i), i=1..2*n-1)];

  for k from 1 do

    t:= add(B[i]*C[i], i=1..2*n-1);

    if isprime(t) then return t fi;

    C:= [op(C[2..-1]), nextprime(C[-1])];

  od

end proc:

map(f, [$2..100]);

CROSSREFS

Sequence in context: A327850 A061525 A293979 * A160359 A142496 A142560

Adjacent sequences:  A340858 A340859 A340860 * A340862 A340863 A340864

KEYWORD

nonn

AUTHOR

J. M. Bergot and Robert Israel, Jan 24 2021

STATUS

approved

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Last modified May 16 08:07 EDT 2021. Contains 343940 sequences. (Running on oeis4.)