%I #8 Nov 13 2016 17:04:34
%S 2,3,9,8,15,23,47,29,66,114,46,220,188,258,640,375,480,589,216,326,
%T 367,1006,738,1183,1985,1847,1662,2224,3731,3861,3561,2699,3792,4521,
%U 2225,12541,3384,12761,3385,4058,10228,15747,15927,14357,18280,19025,14123
%N a(n) = smallest m such that A031131(m) = 2*n.
%C A031131(a(n)) = 2*n and A031131(m) != 2*n for m < a(n);
%C A046931(n) = A000040(a(n)+1);
%C a(n)-th and (a(n)+2)-nd primes are the first pair that differ by 2*n;
%C conjecture: sequence is defined for all n > 1.
%H Reinhard Zumkeller, <a href="/A261525/b261525.txt">Table of n, a(n) for n = 2..100</a>
%o (Haskell)
%o a261525 = (+ 1) . fromJust . (`elemIndex` a031131_list) . (* 2)
%Y Cf. A031131, A038664, A046931.
%K nonn
%O 2,1
%A _Reinhard Zumkeller_, Aug 23 2015