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Central diagonal of A163334 and A163336.
3

%I #6 Nov 06 2020 23:49:06

%S 0,4,8,44,40,36,72,76,80,404,400,396,360,364,368,332,328,324,648,652,

%T 656,692,688,684,720,724,728,3644,3640,3636,3600,3604,3608,3572,3568,

%U 3564,3240,3244,3248,3284,3280,3276,3312,3316,3320,2996,2992,2988

%N Central diagonal of A163334 and A163336.

%C It is easy to see by induction that these terms are always divisible by 4.

%F a(n) = 4*A163344(n).

%F a(n) = A163332(A338086(n)) = A338086(A128173(n)). - _Kevin Ryde_, Nov 06 2020

%o (PARI) a(n) = my(v=digits(n,3),s=Mod(0,2)); for(i=1,#v, if(s,v[i]=2-v[i]); s+=v[i]); fromdigits(v,9)<<2; \\ _Kevin Ryde_, Nov 06 2020

%Y Cf. A163344 (quarter), A128173, A163332, A163334, A338086.

%Y Peano curve axes: A163480, A163481.

%K nonn

%O 0,2

%A _Antti Karttunen_, Jul 29 2009