A264986 - OEIS

%I #8 May 23 2017 20:58:50

%S 0,2,4,6,8,10,12,14,32,18,20,38,24,26,28,30,16,34,36,22,40,42,68,86,

%T 96,50,104,54,56,110,60,74,92,114,44,98,72,62,116,78,80,82,84,46,100,

%U 90,64,118,48,70,88,102,52,106,108,58,112,66,76,94,120,122,284,126,176,338,204,230,248,258,140,302,288

%N Even bisection of A263272; terms of A264974 doubled.

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

%F a(n) = 2 * A264974(n).

%F a(n) = A263273(4*n)/2.

%o (Scheme) (define (A264986 n) (A263272 (+ 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(4*n)/2 # _Indranil Ghosh_, May 23 2017

%Y Cf. A263272, A264974, A264987.

%K nonn

%O 0,2

%A _Antti Karttunen_, Dec 05 2015