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 A157107 #60 Aug 15 2020 09:41:38 %S A157107 220,440,661,881,1105,1325,1546,1766,1991,2211,2432,2652,2876,3096, %T A157107 3317,3537,3771,3991,4212,4432,4656,4876,5097,5317,5542,5762,5983, %U A157107 6203,6427,6647,6868,7088,7326,7546,7767,7987,8211,8431,8652,8872,9097,9317,9538 %N A157107 Indices of 4's in A090822. %C A157107 Despite appearances, this is a highly irregular sequence. - _N. J. A. Sloane_ %C A157107 The first pair of consecutive 4's occurs at position 255895648634818208370064452304769558261700170817472823398081\ %C A157107 655524438021806620809813295008281436789493636145 [Gijswijt, 2016, page 12]. - _Sergio Pimentel_, Feb 21 2017 %C A157107 Comment from _N. J. A. Sloane_, Feb 28 2017: (Start) %C A157107 Page 12 of Gijswijt (2016) states: %C A157107 "In dat stuk vinden we 355 promoties en daarmee 355 stukken lijm van lengte 1, 3, 1, 9, 4, 24, 1, 3, ... Na 355 keer verdubbelen en lijm toevoegen vinden we uiteindelijk de eerste dubbele vier in A090822, en wel op positie %C A157107 255.895.648.634.818.208.370.064.452.304.769.558. %C A157107 261.700.170.817.472.823.398.081.655.524.438.021. %C A157107 806.620.809.813.295.008.281.436.789.493.636.145". %C A157107 A rough translation might be: %C A157107 "... we find 355 promotions and thus 355 glue segments of lengths 1, 3, 1, 9, 4, 24, 1, 3, ... %C A157107 We eventually find the first pair of consecutive 4's in A090822 at position %C A157107 255,895,648,634,818,208,370,064,452,304,769,558, %C A157107 261,700,170,817,472,823,398,081,655,524,438,021, %C A157107 806,620,809,813,295,008,281,436,789,493,636,145." %C A157107 _Dion Gijswijt_, Mar 01 2017 adds that the number mentioned is the position of the second 4 in the first occurrence of 4,4 in A090822. For the glue segments see A091579. %C A157107 (End) %H A157107 Charles R Greathouse IV, <a href="/A157107/b157107.txt">Table of n, a(n) for n = 1..300</a> %H A157107 Dion Gijswijt, <a href="https://pyth.eu/uploads/user/ArchiefPDF/Pyth55-3.pdf">Krulgetallen</a>, Pythagoras, 55ste Jaargang, Nummer 3, Jan 2016. %Y A157107 Cf. A090822, A091579. %K A157107 nonn %O A157107 1,1 %A A157107 _Paul Curtz_, Feb 23 2009 %E A157107 Edited by _N. J. A. Sloane_, Feb 24 2009 %E A157107 More terms from _R. J. Mathar_, Feb 24 2009