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A276567 Odd squares not of the form p + 2^k with p prime. 1


%S 1,40401,62001,96721,121801,192721,326041,410881,555025,660969,683929,

%T 772641,786769,822649,1343281,1390041,1530169,1739761,1885129,1923769,

%U 1962801,2283121,2544025,2913849,3207681,3214849,3352561,3396649,3613801,3775249,3853369,4060225

%N Odd squares not of the form p + 2^k with p prime.

%C The sequence contains also SierpiƄski numbers (i.e., 4521731193704761, 60428287050225649).

%H Robert Israel, <a href="/A276567/b276567.txt">Table of n, a(n) for n = 1..10000</a>

%F A006285 INTERSECT A016754.

%p filter:= proc(n) local k;

%p for k from 0 to ilog2(n) do

%p if isprime(n - 2^k) then return false fi

%p od:

%p true

%p end proc:

%p select(filter, [seq((2*i+1)^2, i=0..10^4)]); # _Robert Israel_, Sep 07 2016

%o (MAGMA) lst:=[]; for s in [1..2015 by 2] do n:=s^2; x:=0; repeat x+:=1; a:=n-2^x; until a lt 1 or IsPrime(a); if a lt 1 then Append(~lst, n); end if; end for; lst;

%Y Cf. A006285, A016754.

%K nonn

%O 1,2

%A _Arkadiusz Wesolowski_, Sep 06 2016

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Last modified November 20 10:09 EST 2019. Contains 329334 sequences. (Running on oeis4.)