login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

a(n) = smallest k such that A114266(k) = n.
1

%I #8 May 01 2013 21:02:09

%S 1,11,4,12,19,13,34,31,36,42,62,59,142,158,247,173,240,273,204,417,

%T 231,669,172,348,965,1003,115,1369,370,1244,1251,1373,983,1109,2489,

%U 1028,2583,1506,6506,6773,7762,5525,2463,6534,6451,3587,4944,3119,3178,4880

%N a(n) = smallest k such that A114266(k) = n.

%C Inverse sequence to A114266.

%t Do[n[k] = 0, {k, 1, 2000}]; ct = 0; nm = 0; n2 = 0; n1 = 1; p1 = 2; While[ct < 200, n2 = 1; p2 = Prime[n1 + n2]; While[cp = 2*p1 + p2; ! PrimeQ[cp], n2++; p2 = Prime[n1 + n2]]; If[n[n2] == 0, n[ n2] = n1; If[n2 > nm, nm = n2]; If[n2 <= 200, ct++ ]; Print[Table[n[k], {k, 1, nm}]]]; n1++; p1 = Prime[n1]]

%Y Cf. A114227, A114230, A073703, A114235, A114262, A114265, A114229, A114232, A114234, A114237, A114264, A114266.

%K nonn

%O 1,2

%A _Lei Zhou_, Nov 20 2005

%E I clarified the definition. - _N. J. A. Sloane_, Jan 08 2011