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A100412 a(n) = 8*10^n - 7.

%I A100412 #25 Apr 14 2023 08:07:08
%S A100412 1,73,793,7993,79993,799993,7999993,79999993,799999993,7999999993,
%T A100412 79999999993,799999999993,7999999999993,79999999999993,
%U A100412 799999999999993,7999999999999993,79999999999999993,799999999999999993
%N A100412 a(n) = 8*10^n - 7.
%C A100412 Also: Numbers n such that n is reversal(n)-th odd number. (This was the original definition. - Ed.)
%C A100412 All semiprimes in this sequence (n = 2, 4, 7, 9, 11, 16, 18, 23, 31, 32, 40, ...) are in A136543. - _M. F. Hasler_, Nov 03 2012
%H A100412 G. C. Greubel, <a href="/A100412/b100412.txt">Table of n, a(n) for n = 0..500</a>
%H A100412 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (11,-10).
%F A100412 From _Colin Barker_, Oct 14 2014: (Start)
%F A100412 a(n) = 10*a(n-1) + a(n-2) - 10*a(n-3).
%F A100412 G.f.: (1+62*x)/((1-x)*(1-10*x)). (End)
%F A100412 E.g.f.: 8*exp(10*x) - 7*exp(x). - _G. C. Greubel_, Apr 14 2023
%e A100412 793 is in the sequence because 793 is 397th odd number.
%e A100412 1 is in the sequence because 1 is the 1st odd number. - _M. F. Hasler_, Nov 03 2012
%t A100412 Table[8*10^n-7, {n,0,20}]
%o A100412 (Maxima) A100412(n):=8*10^n-7$
%o A100412 makelist(A100412(n),n,0,17); /* _Martin Ettl_, Nov 08 2012 */
%o A100412 (PARI) Vec((1+62*x)/((1-x)*(1-10*x)) + O(x^100)) \\ _Colin Barker_, Oct 14 2014
%o A100412 (Magma) [8*10^n -7: n in [0..20]]; // _G. C. Greubel_, Apr 14 2023
%o A100412 (SageMath) [8*10^n -7 for n in range(21)] # _G. C. Greubel_, Apr 14 2023
%Y A100412 Cf. A100413, A136543.
%Y A100412 Sequences of the form m*10^n - 7: 3*A033175 (m=1, 10), A086943 (m=3), 3*A185127 (m=4), A086578 (m=7), this sequence (m=8).
%K A100412 base,easy,nonn
%O A100412 0,2
%A A100412 _Farideh Firoozbakht_, Dec 08 2004
%E A100412 Edited and extended to offset 0 by _M. F. Hasler_, Nov 03 2012