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 A061470 #11 May 24 2021 17:06:05
%S A061470 1,10,21,32,43,54,65,76,87,98,100,111,122,133,144,155,166,177,188,199,
%T A061470 210,221,232,243,254,265,276,287,298,320,331,342,353,364,375,386,397,
%U A061470 430,441,452,463,474,485,496,540,551,562,573,584,595,650,661,672,683
%N A061470 First (leftmost) digit - second digit + third digit - fourth digit .... = 1.
%H A061470 Reinhard Zumkeller, <a href="/A061470/b061470.txt">Table of n, a(n) for n = 1..10000</a>
%F A061470 A225693(a(n)) = 1. - _Reinhard Zumkeller_, Aug 08 2014
%e A061470 221 is in the sequence since 2-2+1 = 1.
%t A061470 d[n_]:=IntegerDigits[n]; a[n_]:=Differences[Reverse[Total/@{Take[d[n],{1,-1,2}],Take[d[n],{2,-1,2}]}]]; Select[Range[690],a[#]=={1} &] (* _Jayanta Basu_, May 18 2013 *)
%t A061470 Select[Range[1000],Total[Times@@@Partition[Riffle[IntegerDigits[#],{1,-1},{2,-1,2}],2]]==1&] (* _Harvey P. Dale_, May 24 2021 *)
%o A061470 (Haskell)
%o A061470 a061470 n = a061470_list !! (n-1)
%o A061470 a061470_list = filter ((== 1) . a225693) [0..]
%o A061470 -- _Reinhard Zumkeller_, Aug 08 2014
%Y A061470 Cf. A008593, A060978-A060980, A060982, A061470-A061479, A061870-A061882.
%Y A061470 Cf. A225693.
%K A061470 nonn,base,easy
%O A061470 1,2
%A A061470 _Amarnath Murthy_, May 05 2001
%E A061470 More terms from _Robert G. Wilson v_, May 10 2001 and from Larry Reeves (larryr(AT)acm.org), May 14 2001