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Number of numbers m <= n such that 4 equals the second digit after decimal point of square root of n in decimal representation.
11

%I #3 Mar 30 2012 18:50:53

%S 0,0,0,0,0,1,2,2,2,2,2,2,2,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,5,5,

%T 5,5,5,5,6,6,6,6,6,6,6,6,6,6,6,6,7,7,7,8,8,8,9,9,9,10,10,10,10,10,10,

%U 10,10,11,11,11,11,11,12,12,12,12,12,12,12,13,13,13,13,13,13,13,13,13,13

%N Number of numbers m <= n such that 4 equals the second digit after decimal point of square root of n in decimal representation.

%e a(10) = 2, a(100) = 17, a(1000) = 121, a(10000) = 1066.

%Y Cf. A111890, A111891, A111892, A111893, A111895, A111896, A111897, A111898, A111899, A111854.

%K nonn,base

%O 1,7

%A _Reinhard Zumkeller_, Aug 20 2005