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Concatenation of first n entries (digits) of A007376 is not divisible by 3.
1

%I #6 Mar 31 2012 10:26:00

%S 1,4,7,10,11,12,14,16,17,18,20,22,23,24,26,28,29,32,34,35,38,40,41,44,

%T 46,47,53,54,59,60,65,66,70,71,72,74,76,77,78,80,82,83,84,86,88,89,92,

%U 94,95,98,100,101,104,106,107,113,114,119,120,125,126,130,131,132,134

%N Concatenation of first n entries (digits) of A007376 is not divisible by 3.

%C Concatenation of some permutations of the n digits of A007376 is likely to be prime.

%e 16 is in the sequence because the 16-digit number 1234567891011121 = 1 (mod 3).

%t f[0] = 0; f[n_Integer] := 10^(Floor[Log[10, n]] + 1)*f[n - 1] + n; Select[ Range[140], Mod[ FromDigits[ Take[ IntegerDigits[ f[n]], n]], 3] != 0 &]

%Y Cf. A007376 & A033307.

%K easy,nonn,base

%O 1,2

%A _Lekraj Beedassy_, Jun 20 2002

%E Edited by _Robert G. Wilson v_, Jun 21 2002