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a(n) = 1 if A276150(n) is a multiple of 3, otherwise 0, where A276150 is the digit sum in the primorial base.
3

%I #8 Jun 20 2024 08:38:07

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

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

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

%N a(n) = 1 if A276150(n) is a multiple of 3, otherwise 0, where A276150 is the digit sum in the primorial base.

%H Antti Karttunen, <a href="/A373840/b373840.txt">Table of n, a(n) for n = 0..100000</a>

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

%H <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>

%F a(n) = A079978(A276150(n)).

%o (PARI)

%o A276150(n) = { my(s=0, p=2, d); while(n, d = (n%p); s += d; n = (n-d)/p; p = nextprime(1+p)); (s); };

%o A373840(n) = !(A276150(n)%3);

%Y Characteristic function of A373841.

%Y Cf. A079978, A276150.

%Y Cf. also A373838, A373830.

%K nonn,base

%O 0

%A _Antti Karttunen_, Jun 20 2024