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Number of times the digit 1 appears in the decimal expansion of n^3.
12

%I #24 Feb 22 2016 22:14:02

%S 0,1,0,0,0,1,1,0,1,0,1,2,1,1,0,0,0,1,0,0,0,1,1,2,1,1,1,1,1,0,0,1,0,0,

%T 0,0,0,0,0,1,0,1,0,0,1,2,0,1,2,2,1,2,1,1,1,1,2,2,3,0,1,1,0,0,1,0,0,0,

%U 1,0,0,2,0,1,0,1,0,0,0,0,1,2,1,1,0,2,0,0,1,0,0,1,0,0,0,0

%N Number of times the digit 1 appears in the decimal expansion of n^3.

%C The cubes corresponding to the first occurrence of 1, 2, 3, ... are listed in A036528, i.e., A036528(n)^(1/3) = A048366(n) is the index of the first occurrence of n.

%e 0^3 = 0 has a(0) = 0 digits '1'.

%e 1^3 = 1 has a(1) = 1 digit '1'.

%e 2^3 = 8 has a(2) = 0 digits '1'.

%e 3^3 = 27 has a(3) = 0 digits '1'.

%e 4^3 = 64 has a(4) = 0 digits '1'.

%e 5^3 = 125 has a(5) = 1 digit '1'.

%e 11^3 = 1331 is the smallest cube to have a(11) = 2 digits '1'.

%t Table[DigitCount[n^3, 10, 1], {n, 0, 99}] (* _Alonso del Arte_, Feb 20 2016 *)

%o (PARI) A269241(n)=#select(t->t==1,digits(n^3))

%Y Cf. A036528 and A036527 - A036536; A048366 and A048365 - A048374.

%Y Analog for the other digits 0, 2, ..., 9: A269250, A269242, A269243, A269244, A269245, A269246, A269247, A269248, A269249.

%Y Analog for squares: A086009 (digit 1), and A086008 - A086017 for digits 0 - 9.

%K nonn,base

%O 0,12

%A _M. F. Hasler_, Feb 20 2016