cp's OEIS Frontend

A345143 Reflection of the concatenation of the previous two terms minus the previous term.

%I A345143 #22 Jun 11 2021 17:29:50
%S A345143 0,1,9,82,207,70021,11937681,1867379174326,623471971900739499585,
%T A345143 5859949370091168271294333980238096,
%U A345143 6908320893334921728606040790129494417723642675198936230
%N A345143 Reflection of the concatenation of the previous two terms minus the previous term.
%F A345143 a(n) = A004086(a(n-2)||a(n-1)) - a(n-1) for n >= 2, a(n) = n for n <= 1.
%e A345143 a(4) = 207 since 28(9) - 82 = 207.
%p A345143 a:= proc(n) option remember; `if`(n<2, n, (s-> parse(cat(seq(
%p A345143       s[-i], i=1..length(s))))-a(n-1))(cat("", a(n-2), a(n-1))))
%p A345143     end:
%p A345143 seq(a(n), n=0..11);  # _Alois P. Heinz_, Jun 11 2021
%t A345143 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 A345143 (Python)
%o A345143 def f(v): return int((str(v[-2])+str(v[-1]))[::-1]) - v[-1]
%o A345143 def aupton(nn):
%o A345143     alst = [0, 1]
%o A345143     for n in range(2, nn+1): alst.append(f(alst))
%o A345143     return alst[:nn+1]
%o A345143 print(aupton(10)) # _Michael S. Branicky_, Jun 09 2021
%Y A345143 Cf. A004086, A068109.
%K A345143 nonn,base
%O A345143 0,3
%A A345143 _George Bull_, Jun 09 2021