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!)
 A109213 Product of a(n-2) and digit reversal of a(n-1). 2
 1, 2, 2, 4, 8, 32, 184, 15392, 5400584, 74651892640, 25003708306137848, 6335942056759761366725617280, 20682199297864337408779128828731176793076928 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Cf. A000301 a(n) = a(n-1)*a(n-2), A004086 R(n) = digit reversal of n, A109214 a(n)=a(n-1)*R(a(n-2)). LINKS FORMULA a(n)=a(n-2)*R(a(n-1)). EXAMPLE a(5)=8, a(6)=32, R(32)=23, hence a(7)=8*23=184; R(184)=841, a(8)=32*841=15392, etc. MATHEMATICA a[1]=1; a[2]=2; a[n_]:=a[n]=a[n-2]*FromDigits[Reverse[IntegerDigits[a[n-1]]]]; A109213=Table[a[n], {n, 13}] nxt[{a_, b_}]:={b, a*IntegerReverse[b]}; NestList[nxt, {1, 2}, 15][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 09 2017 *) CROSSREFS Cf. A000301, A004086, A109214. Sequence in context: A300759 A100799 A070323 * A109214 A000301 A124439 Adjacent sequences:  A109210 A109211 A109212 * A109214 A109215 A109216 KEYWORD base,nonn AUTHOR Zak Seidov, Jun 22 2005 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 September 24 07:28 EDT 2020. Contains 337317 sequences. (Running on oeis4.)