The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A181755 a(1) = 1, a(2) = 5. For n >= 3, a(n) is found by concatenating the first n-1 terms of the sequence and then dividing the resulting number by a(n-1). 9
 1, 5, 3, 51, 301, 51001, 30100001, 5100100000001, 301000010000000000001, 5100100000001000000000000000000001, 3010000100000000000010000000000000000000000000000000001 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The calculations for the first few values of the sequence are ... a(3) = 15/5 = 3 ... a(4) = 153/3 = 51 ... a(5) = 15351/51 = 301 ... a(6) = 15351301/301 = 51001. For similarly defined sequences see A181754, A184756 and A181864 through A181870. LINKS FORMULA DEFINITION a(1) = 1, a(2) = 5, and for n >= 3 (1)... a(n) = concatenate(a(1),a(2),...,a(n-1))/a(n-1). RECURRENCE RELATION For n >= 2 (2)... a(n+2) = 10^F(n)*a(n)+1, where F(n) = A000045(n) are the Fibonacci numbers. For n >= 2, a(n) has F(n-1) digits. MAPLE M:=11: a:=array(1..M):s:=array(1..M): a[1]:=1:a[2]:=5: s[1]:=convert(a[1], string): s[2]:=cat(s[1], convert(a[2], string)): for n from 3 to M do a[n] := parse(s[n-1])/a[n-1]; s[n]:= cat(s[n-1], convert(a[n], string)); end do: seq(a[n], n = 1..M); MATHEMATICA nxt[lst_]:=Module[{nt=FromDigits[Flatten[IntegerDigits/@lst]]/Last[ lst]}, Flatten[{lst, nt}]]; Nest[nxt[#]&, {1, 5}, 10] (* Harvey P. Dale, Aug 08 2014 *) CROSSREFS Cf. A000045, A181754, A181756, A181864, A181865, A181866, A181867, A181868, A181869, A181870 Sequence in context: A323779 A343290 A027858 * A007299 A257935 A109254 Adjacent sequences:  A181752 A181753 A181754 * A181756 A181757 A181758 KEYWORD easy,nonn,base AUTHOR Peter Bala, Nov 09 2010 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified July 31 06:15 EDT 2021. Contains 346369 sequences. (Running on oeis4.)