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 A181867 a(1) = 2, a(2) = 1. For n >= 3, a(n) is found by concatenating the first n-1 terms of the sequence in reverse order and then dividing the resulting number by a(n-1). 9
 2, 1, 12, 101, 10012, 10000101, 1000000010012, 100000000000010000101, 1000000000000000000001000000010012, 1000000000000000000000000000000000100000000000010000101 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Compare with A181754. Here we concatenate the terms of the sequence in reverse order before dividing by a(n-1). The calculations for the first few values of the sequence are ... a(3) = 12/1 = 12 ... a(4) = 1212/12 = 101 ... a(5) = 1011212/101 = 10012 ... a(6) = 100121011212/10012 = 10000101. For similarly defined sequences see A181864 through A181870. LINKS FORMULA DEFINITION a(1) = 2, a(2) = 1, and for n >= 3 (1)... a(n) = concatenate(a(n-1),a(n-2),...,a(1))/a(n-1). RECURRENCE RELATION For n >= 2 (2)... a(n+2) = a(n) + 10^(F(n)-1), where F(n) = A000045(n) are the Fibonacci numbers. a(n) has F(n) digits. MAPLE M:=10: a:=array(1..M):s:=array(1..M): a:=2:a:=1: s:=convert(a, string): s:=cat(convert(a, string), s): for n from 3 to M do a[n] := parse(s[n-1])/a[n-1]; s[n]:= cat(convert(a[n], string), s[n-1]); end do: seq(a[n], n = 1..M); CROSSREFS A000045, A181754, A181755, A181756, A181864, A181865, A181866, A181868, A181869, A181870 Sequence in context: A012585 A053566 A009483 * A231611 A171510 A106750 Adjacent sequences:  A181864 A181865 A181866 * A181868 A181869 A181870 KEYWORD nonn,easy,base AUTHOR Peter Bala, Nov 28 2010 STATUS approved

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Last modified August 12 12:09 EDT 2020. Contains 336439 sequences. (Running on oeis4.)