This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A016181 #24 Mar 26 2025 13:29:19
%S A016181 1,17,219,2533,27731,294117,3058819,31411733,319882131,3239174917,
%T A016181 32674224419,328719570933,3301036996531,33107258975717,
%U A016181 331750812830019,3322255689810133,33255789828670931,332790528800696517,3329533701604875619,33306735911234129333,333147151378638905331
%N A016181 Expansion of g.f. 1/((1-7*x)*(1-10*x)).
%H A016181 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (17,-70).
%F A016181 a(n) = (10^(n+1) - 7^(n+1))/3. - Lambert Klasen (lambert.klasen(AT)gmx.net), Feb 05 2005
%F A016181 From _Vincenzo Librandi_, Feb 09 2011: (Start)
%F A016181 a(n) = 10*a(n-1) + 7^n, a(0)=1.
%F A016181 a(n) = 17*a(n-1) - 70*a(n-2), a(0)=1, a(1)=17. (End)
%F A016181 From _Elmo R. Oliveira_, Mar 26 2025: (Start)
%F A016181 E.g.f.: exp(7*x)*(10*exp(3*x) - 7)/3.
%F A016181 a(n) = A248341(n+1)/3. (End)
%t A016181 Join[{a=1,b=17},Table[c=17*b-70*a;a=b;b=c,{n,40}]] (* _Vladimir Joseph Stephan Orlovsky_, Feb 09 2011 *)
%t A016181 CoefficientList[Series[1/((1-7x)(1-10x)),{x,0,30}],x] (* or *) LinearRecurrence[ {17,-70},{1,17},30] (* _Harvey P. Dale_, Nov 16 2020 *)
%o A016181 (PARI) for(n=1,10,print1((10^n-7^n)/3,","))
%Y A016181 Cf. A248341.
%K A016181 nonn,easy
%O A016181 0,2
%A A016181 _N. J. A. Sloane_
%E A016181 More terms from _Elmo R. Oliveira_, Mar 26 2025