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%I #22 Jun 11 2021 17:29:50
%S 0,1,9,82,207,70021,11937681,1867379174326,623471971900739499585,
%T 5859949370091168271294333980238096,
%U 6908320893334921728606040790129494417723642675198936230
%N Reflection of the concatenation of the previous two terms minus the previous term.
%F a(n) = A004086(a(n-2)||a(n-1)) - a(n-1) for n >= 2, a(n) = n for n <= 1.
%e a(4) = 207 since 28(9) - 82 = 207.
%p a:= proc(n) option remember; `if`(n<2, n, (s-> parse(cat(seq(
%p s[-i], i=1..length(s))))-a(n-1))(cat("", a(n-2), a(n-1))))
%p end:
%p seq(a(n), n=0..11); # _Alois P. Heinz_, Jun 11 2021
%t a[0] = 0; a[1] = 1; a[n_] := a[n] = FromDigits[Join @@ (Reverse @ IntegerDigits[#] & /@ {a[n - 1], a[n - 2]})] - a[n - 1]; Array[a, 11, 0] (* _Amiram Eldar_, Jun 09 2021 *)
%o (Python)
%o def f(v): return int((str(v[-2])+str(v[-1]))[::-1]) - v[-1]
%o def aupton(nn):
%o alst = [0, 1]
%o for n in range(2, nn+1): alst.append(f(alst))
%o return alst[:nn+1]
%o print(aupton(10)) # _Michael S. Branicky_, Jun 09 2021
%Y Cf. A004086, A068109.
%K nonn,base
%O 0,3
%A _George Bull_, Jun 09 2021
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