A264984 - OEIS

%I #12 May 22 2017 20:07:42

%S 0,2,4,6,8,10,12,22,16,18,20,14,24,26,28,30,64,46,36,58,40,66,76,34,

%T 48,70,52,54,56,38,60,74,32,42,68,50,72,62,44,78,80,82,84,190,136,90,

%U 172,118,192,226,100,138,208,154,108,166,112,174,220,94,120,202,148,198,184,130

%N Even bisection of A263273; terms of A263262 doubled.

%F a(n) = 2 * A263272(n).

%F a(n) = A263273(2*n).

%F Other identities. For all n >= 0:

%F A010873(a(n)) = 2 * A000035(n) = A010673(n).

%o (Scheme) (define (A264984 n) (A263273 (+ n n)))

%o (Python)

%o from sympy import factorint

%o from sympy.ntheory.factor_ import digits

%o from operator import mul

%o def a030102(n): return 0 if n==0 else int(''.join(map(str, digits(n, 3)[1:][::-1])), 3)

%o def a038502(n):

%o     f=factorint(n)

%o     return 1 if n==1 else reduce(mul, [1 if i==3 else i**f[i] for i in f])

%o def a038500(n): return n/a038502(n)

%o def a263273(n): return 0 if n==0 else a030102(a038502(n))*a038500(n)

%o def a(n): return a263273(2*n) # _Indranil Ghosh_, May 22 2017

%Y Cf. A000035, A010673, A010873, A263272, A263273, A264983, A264975.

%K nonn

%O 0,2

%A _Antti Karttunen_, Dec 05 2015