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%I #21 Jun 27 2017 15:35:47
%S 12,18,20,32,44,68,98,164,212,242,284,332,338,524,548,578,692,788,908,
%T 1052,1124,1172,1532,1724,1868,2012,2084,2252,2348,2372,2468,2708,
%U 2732,2804,2972,3188,3308,3362,3548,3644,3698,3908,3932,4052,4244,4364,4604,4652
%N Numbers that are 1+prime and have 4 proper divisors.
%H Lars Blomberg, <a href="/A259980/b259980.txt">Table of n, a(n) for n = 1..10000</a>
%H R. P. Boas & N. J. A. Sloane, <a href="/A005381/a005381.pdf">Correspondence, 1974</a>
%e 12 is 1+11, and has the proper divisors 2, 3, 4, 6.
%t Select[Prime@ Range@ 630 + 1, DivisorSigma[0, #] == 6 &] (* _Michael De Vlieger_, Jul 13 2015 *)
%o (PARI) main(size)={my(v=vector(size),i,t);t=1;for(i=1,size,until(length(divisors(prime(t)+1))-2==4,t++);v[i]=prime(t)+1;t++);return(v);} /* _Anders Hellström_, Jul 13 2015 */
%Y Cf. A008864.
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_, Jul 12 2015, following a suggestion from R. P. Boas, May 19 1974
%E More terms from _Lars Blomberg_, Jul 13 2015
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