|
%I #13 Jan 04 2019 18:37:50
%S 3,11,59,139,179,311,419,541,919,1399,1621,2111,3119,5099,6379,8059,
%T 8839,9377,15661,16007,16741,17107,21011,21839,23539,24419,28081,
%U 30011,31489,33533,35617,37811,39461,41759,44699,45293,60899,68819,71059,78007,83639,84457,86111
%N Lesser of consecutive primes whose sum is of the form k*(k+2), for some integer k.
%H Harvey P. Dale, <a href="/A242384/b242384.txt">Table of n, a(n) for n = 1..500</a>
%e 311 is in the sequence because 311 is prime, nextprime(311)=313, and 311+313 = 624 = 24*(24+2).
%t Select[Partition[Prime[Range[9000]],2,1],IntegerQ[Sqrt[1+Total[#]]-1]&] [[All,1]] (* _Harvey P. Dale_, May 15 2017 *)
%o (PARI) {k=2;while(k<10^5,l=nextprime(k+1);if(issquare(k+l+1),print1(k,", "));k=l)}
%Y Cf. A242383, A242385.
%K nonn
%O 1,1
%A _Antonio Roldán_, May 12 2014
|
