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Primes p of the form 4k + 3 such that A000120(p) >= A000120(3p).
1

%I #42 Feb 13 2021 14:00:52

%S 3,7,11,23,31,43,47,59,103,107,127,139,151,179,191,199,223,227,239,

%T 251,283,311,347,359,367,379,383,431,439,443,463,479,487,491,499,503,

%U 523,571,599,607,619,631,683,691,719,727,739,743,751,811,823,827,859,863,883,887,907,911,919

%N Primes p of the form 4k + 3 such that A000120(p) >= A000120(3p).

%H Robert Israel, <a href="/A239227/b239227.txt">Table of n, a(n) for n = 1..10000</a>

%p N:= 1000: # to get all entries <= 4*N+3

%p P:= select(isprime,[seq(4*i+3,i=0..N)]):

%p select(p -> convert(convert(p,base,2),`+`)>=convert(convert(3*p,base,2),`+`),P);

%p # _Robert Israel_, Jun 08 2014

%o (PARI) isok(p) = ((p%4) == 3) && (hammingweight(p) >= hammingweight(3*p)) && isprime(p); \\ _Michel Marcus_, Feb 13 2021

%Y Cf. A000120, A002145.

%K nonn

%O 1,1

%A _Irina Gerasimova_, Mar 12 2014, a sockpuppet of _Juri-Stepan Gerasimov_.