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%I #11 May 16 2022 10:04:38
%S 0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,
%T 0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,
%U 0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,1
%N a(n) = 1 if n > 1 and n is a power of a Pythagorean prime (prime of the form 4m+1), otherwise 0.
%H Antti Karttunen, <a href="/A354031/b354031.txt">Table of n, a(n) for n = 1..65539</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%F a(n) = [A024362(n) == 1], where [ ] is the Iverson bracket.
%F a(n) = A174275(n) - A354033(n).
%F a(n) <= A354030(n).
%o (PARI) A354031(n) = { my(p=0); (isprimepower(n,&p) && (1==(p%4))); };
%Y Characteristic function of A120960, Pythagorean prime powers.
%Y Cf. A002144, A024362, A174275, A354030, A354033.
%K nonn
%O 1
%A _Antti Karttunen_, May 15 2022
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