This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A015948 #10 Mar 30 2012 18:35:07 %S A015948 1,2,5,4,7,10,15,8,11,14,13,28,21,78,17,16,19,22,49,42,23,26,1577,40, %T A015948 33,30,29,44,31,34,39,32,65,38,37,52,115,102,41,242,43,46,51,60,47, %U A015948 279,395,152,57,114,53,68,85,58,63,104,59,62,61,76,69,126,5773,64,67,1090 %N A015948 a(n) = smallest k >= n such that k | (2^k + n). %C A015948 Equally, a(n) = smallest k with 2^k mod k = k - n. %F A015948 a(p-2) = p for p prime >= 5; a(2^k) = 2^k. - _David W. Wilson_ %Y A015948 Cf. A015910, A036236. %K A015948 nonn %O A015948 0,2 %A A015948 _Robert G. Wilson v_ %E A015948 Edited by _N. J. A. Sloane_, Jan 31 2009 at the suggestion of R. J. Mathar and T. D. Noe. %E A015948 Restricted the range of k in the definition - _R. J. Mathar_, Mar 07 2010