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a(n) = 1 if n>1 and sigma(A156552(n)) is congruent to 2 modulo 4, otherwise a(n) = 0.
4

%I #7 Mar 16 2019 21:45:33

%S 0,0,0,0,0,1,0,0,0,0,0,0,0,1,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,

%T 1,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,1,0,0,0,

%U 1,1,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,1,0

%N a(n) = 1 if n>1 and sigma(A156552(n)) is congruent to 2 modulo 4, otherwise a(n) = 0.

%H Antti Karttunen, <a href="/A324824/b324824.txt">Table of n, a(n) for n = 1..10000</a> (based on Hans Havermann's factorization of A156552)

%H <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>

%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>

%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>

%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>

%o (PARI)

%o A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552 by _David A. Corneth_

%o A324824(n) = ((n>1)&&(2==(sigma(A156552(n))%4)));

%o (PARI) A324824(n) = (2==(A323243(n)%4)); \\ This needs code also from A323243.

%Y Characteristic function of A324814.

%Y Cf. A156552, A191217, A324822, A324823.

%K nonn

%O 1

%A _Antti Karttunen_, Mar 16 2019