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 A121065 #15 Jul 13 2025 14:07:44 %S A121065 2,0,3,11,17,111,117,317,1317,3317,11317,17317,111317,117317,317317, %T A121065 1317317,3317317,11317317,17317317,111317317,117317317,317317317, %U A121065 1317317317,3317317317,11317317317,17317317317,111317317317,117317317317,317317317317,1317317317317 %N A121065 a(n) is the smallest number in English which contains n letter 'E's. %C A121065 4, 5, 6, 8, 9 never appear in any of these numbers because in each case there is a smaller digit with the same number of e's. 2 (the smallest number with no e's) never appears in any term after a(0). - _Sean A. Irvine_, Nov 10 2009 %C A121065 A085513(a(n)) = n and A085513(m) != n for m < a(n). - _Reinhard Zumkeller_, Jan 24 2015 %H A121065 <a href="/index/Lc#letters">Index entries for sequences related to number of letters in n</a> %F A121065 From _Chai Wah Wu_, Dec 20 2019: (Start) %F A121065 a(n) = a(n-1) + 1000*a(n-7) - 1000*a(n-8) for n > 9 (conjectured). %F A121065 G.f.: (-1000*x^9 + 3000*x^8 - 1800*x^7 + 6*x^6 + 94*x^5 + 6*x^4 + 8*x^3 + 3*x^2 - 2*x + 2)/((x - 1)*(1000*x^7 - 1)) (conjectured). (End) %e A121065 a(2) = THREE, which has two Es. %o A121065 (Haskell) %o A121065 import Data.List (elemIndex); import Data.Maybe (fromJust) %o A121065 a121065 = fromJust . (`elemIndex` a085513_list) %o A121065 -- _Reinhard Zumkeller_, Jan 24 2015 %Y A121065 Cf. A085513, A008520, A006933. Variant of A036448. %K A121065 nonn,word %O A121065 0,1 %A A121065 _Ray G. Opao_, Aug 10 2006 %E A121065 More terms _Sean A. Irvine_, Nov 10 2009 %E A121065 a(19) - a(21) added by _Reinhard Zumkeller_, Jan 24 2015 %E A121065 a(22) - a(29) from _Chai Wah Wu_, Dec 20 2019