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%I #24 Sep 08 2022 08:46:11
%S 0,6,238,31710,16510910,34089189246,280371153272574,
%T 9205322385119247870,1207744073945406663293950,
%U 633515663914742881158342637566,1328903397983747395279166325955489790,11149011303623843458013522930838119932485630,374121581799746201009538413109130562019709006364670
%N Decimal equivalent of the binary string generated by the negation of the n X n identity matrix.
%H Stuart Bruff, <a href="/A256275/b256275.txt">Table of n, a(n) for n = 1..26</a>
%F a(n) = 2^(n^2) - (1 + (2^((n+1)*(n-1)) + 2^((n+1)*(n-2) + .. 1))).
%F a(n) = 2^(n^2) - (1 + A119408(n)).
%F a(n) = ((2^(n^2) - 2)*(2^n - 1))/(2*2^n - 1)
%e For n = 3, a(3) = 2^(3^2) - (1 + (2^((3+1)*(3-1)) + 2^((3+1)*(3-2)) + 2^((3+1)*(3-3)))) = 2^9 - (1 + (2^8 + 2^4 + 2^0)) = 512 - (1 + (256 + 16 + 1)) = 512 - 274 = 238.
%p seq((2^(n^2)-2)*(1-2^n)/(1-2^(n+1)),n=1..26); # _Robert Israel_, Jun 02 2015
%t Table[2^(n^2) - (1 + Sum[2^((n + 1) (n - k)), {k, n}]), {n, 12}] (* _Michael De Vlieger_, Jun 02 2015 *)
%o (Mathcad) 2^(n^2) - (1 + Summation[k=1..n (2^((n+1).(n-k)))])
%o (Magma) [(2^(n^2)-2)*(1-2^n)/(1-2^(n+1)): n in [1..15]]; // _Vincenzo Librandi_, Jun 03 2015
%Y Cf. A119408.
%K nonn
%O 1,2
%A _Stuart Bruff_, Jun 02 2015
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