login

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

a(n) is the number of primes 2^(n-1) <= p < 2^n with maximal Hamming weight A091937(n-1) in this interval.
3

%I #9 Apr 09 2020 11:10:31

%S 1,1,2,1,3,1,4,4,3,1,5,1,4,18,3,1,8,1,11,4,5,31,7,1,2,33,1,5,4,1,7,5,

%T 1,1,9,55,6,71,7,1,6,69,4,7,2,1,10,3,3,1,2,1,6,95,4,3,61,1,8,1,3,110,

%U 3,1,8,1,2,2,3,98,9,1,5,2,5,8,3,125,10,3,81,2

%N a(n) is the number of primes 2^(n-1) <= p < 2^n with maximal Hamming weight A091937(n-1) in this interval.

%H Giovanni Resta, <a href="/A333879/b333879.txt">Table of n, a(n) for n = 2..1000</a>

%t a[2]=1; a[n_] := Block[{c = 0, nb = 0}, While[c == 0, c = Count[2^n - 1 - Total /@ Subsets[2^Range[n - 2], {nb}], x_ /; PrimeQ[x]]; nb++]; c]; a /@ Range[2, 85] (* _Giovanni Resta_, Apr 09 2020 *)

%Y Cf. A091937, A091938, A333877, A333878.

%K nonn

%O 2,3

%A _Hugo Pfoertner_, Apr 08 2020

%E Terms a(35) and beyond from _Giovanni Resta_, Apr 09 2020