A345143 Reflection of the concatenation of the previous two terms minus the previous term.
0, 1, 9, 82, 207, 70021, 11937681, 1867379174326, 623471971900739499585, 5859949370091168271294333980238096, 6908320893334921728606040790129494417723642675198936230
Offset: 0
Examples
a(4) = 207 since 28(9) - 82 = 207.
Programs
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Maple
a:= proc(n) option remember; `if`(n<2, n, (s-> parse(cat(seq( s[-i], i=1..length(s))))-a(n-1))(cat("", a(n-2), a(n-1)))) end: seq(a(n), n=0..11); # Alois P. Heinz, Jun 11 2021 -
Mathematica
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 *) -
Python
def f(v): return int((str(v[-2])+str(v[-1]))[::-1]) - v[-1] def aupton(nn): alst = [0, 1] for n in range(2, nn+1): alst.append(f(alst)) return alst[:nn+1] print(aupton(10)) # Michael S. Branicky, Jun 09 2021
Formula
a(n) = A004086(a(n-2)||a(n-1)) - a(n-1) for n >= 2, a(n) = n for n <= 1.