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 A101868 #19 May 18 2025 02:14:52 %S A101868 5,10,13,18,23,26,31,34,39,44,47,52,57,60,65,68,73,78,81,86,89,94,99, %T A101868 102,107,112,115,120,123,128,133,136,141,146,149,154,157,162,167,170, %U A101868 175,178,183,188,191,196,201,204,209,212,217,222,225,230,233,238,243,246,251,256 %N A101868 a(n) = n + 2*ceiling(phi*n), where phi = (1 + sqrt(5))/2. Row 1 of A101866. %C A101868 Positions of 1 in A188009 = (0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0,...) %C A101868 A101868 = (5, 10, 13, 18, 23, 26, 31, 34, 39, 44, 47, 52, 57, 60, ...). - _Clark Kimberling_, Mar 19 2011, corrected by _M. F. Hasler_, Oct 12 2017 %C A101868 Essentially the same as A188434, which has an initial 2 prefixed. However, the present sequence would have a(0) = 0 if extended to offset / index 0. - _M. F. Hasler_, Oct 12 2017 %H A101868 Paolo Xausa, <a href="/A101868/b101868.txt">Table of n, a(n) for n = 1..10000</a> %t A101868 Array[# + 2*Ceiling[#*GoldenRatio] &, 100] (* _Paolo Xausa_, Mar 20 2024 *) %o A101868 (PARI) a(n)=n+2*ceil(quadgen(5)*n+.) \\ _M. F. Hasler_, Oct 12 2017 %Y A101868 Cf. A188009, A101868, A188434. %Y A101868 Cf. A001622, A101866. %K A101868 nonn %O A101868 1,1 %A A101868 _N. J. A. Sloane_, Jan 28 2005