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 A115419 #34 Mar 29 2024 02:23:08
%S A115419 8,9,10,11,12,13,14,15,24,25,26,27,28,29,30,31,40,41,42,43,44,45,46,
%T A115419 47,56,57,58,59,60,61,62,63,72,73,74,75,76,77,78,79,88,89,90,91,92,93,
%U A115419 94,95,104,105,106,107,108,109,110,111,120,121,122,123,124,125,126,127
%N A115419 Numbers having a 1 in position 3 of their binary expansion.
%C A115419 One of the mystery calculator sequences: A005408, A042964, A047566, A115419, A115420, A115421.
%C A115419 Numbers congruent to {8,9,10,11,12,13,14,15} mod 16. Numbers n such that n xor 8 = n - 8. [_Brad Clardy_, May 06 2013]
%H A115419 Edd Mann, <a href="https://eddmann.com/mystery-calculator-clojurescript/">Mystery Calculator</a>.
%H A115419 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,0,1,-1).
%F A115419 G.f.: -(x^8+x^7+x^6+x^5+x^4+x^3+x^2+x+8)*x / (-x^9+x^8+x-1). - _Alois P. Heinz_, Aug 22 2011
%e A115419 a(1) = 8 = 1000 in binary.
%p A115419 a:= n-> n+7 + 8*iquo(n-1, 8):
%p A115419 seq(a(n), n=1..100); # _Alois P. Heinz_, Aug 22 2011
%o A115419 (PARI) a(n)=(n-1)\8*16+(n-1)%8+8 \\ _Charles R Greathouse IV_, May 06 2013
%o A115419 (Python)
%o A115419 def A115419(n): return ((n-1<<1)&-7|8)+(n-1&7) # _Chai Wah Wu_, Mar 28 2024
%Y A115419 Cf. A005408, A042964, A047566, A115420, A115421.
%K A115419 base,easy,nonn
%O A115419 1,1
%A A115419 _Jeremy Gardiner_, Jan 22 2006