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Numbers having a 1 in position 4 of their binary expansion.
6

%I #14 Mar 29 2024 02:22:51

%S 16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,48,49,50,51,52,53,54,

%T 55,56,57,58,59,60,61,62,63,80,81,82,83,84,85,86,87,88,89,90,91,92,93,

%U 94,95,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127

%N Numbers having a 1 in position 4 of their binary expansion.

%C One of the mystery calculator sequences: A005408, A042964, A047566, A115419, A115420, A115421.

%H Edd Mann, <a href="https://eddmann.com/mystery-calculator-clojurescript/">Mystery Calculator</a>.

%e a(1) = 16 = 10000 in binary.

%p a:= n-> n+15 + 16*iquo(n-1, 16):

%p seq(a(n), n=1..100); # _Alois P. Heinz_, Aug 22 2011

%o (Python)

%o def A115420(n): return ((n-1<<1)&-15|16)+(n-1&15) # _Chai Wah Wu_, Mar 28 2024

%Y Cf. A005408, A042964, A047566, A115419, A115421.

%K base,easy,nonn

%O 1,1

%A _Jeremy Gardiner_, Jan 22 2006