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a(n) = A014824(2*n-1).
1

%I #30 Feb 24 2024 01:09:15

%S 1,123,12345,1234567,123456789,12345679011,1234567901233,

%T 123456790123455,12345679012345677,1234567901234567899,

%U 123456790123456790121,12345679012345679012343

%N a(n) = A014824(2*n-1).

%C Previous name was: Numbers whose square root shows strings of seemingly rational and irrational strings.

%H Muniru A Asiru, <a href="/A095761/b095761.txt">Table of n, a(n) for n = 1..101</a>

%H K. S. Brown, <a href="http://www.mathpages.com/home/kmath404.htm">Schizophrenic numbers</a>

%F a(1) = 1; for n > 1, a(n) = 100*a(n - 1) + 22*n - 21.

%F O.g.f.: x(1+21x)/((-1+x)^2*(1-100x)) = -17/(81(-1+x)) - 1/(81(-1+100*x)) - 2/(9(-1+x)^2). - _R. J. Mathar_, Feb 01 2008

%t RecurrenceTable[{a[1]==1, a[n]==100 a[n-1] + 22 n - 21}, a, {n, 20}] (* _Vincenzo Librandi_, Apr 03 2018 *)

%o (PARI) a=vector(10^3); a[1]=1; for(n=2, #a, a[n]=100*a[n-1]+22*n-21); a \\ _Altug Alkan_, Mar 30 2018

%o (GAP) a:=[1];; for n in [2..20] do a[n]:=100*a[n-1]+22*n-21; od; a; # _Muniru A Asiru_, Mar 30 2018

%o (Magma) [-19/81-(2/9)*(n-1)+(100/81)*100^(n-1): n in [1..20]]; // _Vincenzo Librandi_, Apr 03 2018

%Y Cf. A014824.

%K easy,nonn,base

%O 1,2

%A _Michael Joseph Halm_, Jul 10 2004

%E Better name from _Georg Fischer_, Mar 30 2018