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A160358 Indices of primes in A133547, i.e., numbers n such that the sum of the squares of the first n odd primes is prime. 1

%I

%S 3,5,9,11,23,29,63,65,71,95,141,159,161,173,179,183,209,219,255,299,

%T 323,341,365,371,389,393,453,485,521,567,579,605,623,633,635,639,677,

%U 701,711,723,725,747,785,827,867,945,981,993,999,1001,1013,1035,1037,1041

%N Indices of primes in A133547, i.e., numbers n such that the sum of the squares of the first n odd primes is prime.

%C All terms are necessarily odd. Thus one could also consider the sequence floor(a(n)/2) = (1,2,4,5,11,14,31,32,35,...). Other possible variations would be to list the index a(n)+1 of the largest prime in that sum, or, since this is always even, (a(n)+1)/2 = (2,3,5,6,12,15,32,33,36,...).

%F A160359(n) = A133547(a(n)) = A024450(a(n)+1) - 4.

%o (PARI) s=0; for( i=2,1999, isprime(s+=prime(i)^2) & print1(i-1,","))

%Y Cf. A098561, A133547.

%K nonn

%O 1,1

%A _M. F. Hasler_, May 18 2009

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Last modified February 7 22:10 EST 2023. Contains 360132 sequences. (Running on oeis4.)