OFFSET
1,1
COMMENTS
There are Fibonacci(floor((k-2)/2)) terms with k digits (this is essentially A103609). - Ray Chandler, Oct 12 2017
REFERENCES
D. Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986.
LINKS
Ray Chandler, Table of n, a(n) for n = 1..10000 (first 200 terms from Vincenzo Librandi)
C. A. Van Cott, The Integer Hokey Pokey, Math Horizons, Vol. 28, pp. 24-27, November 2020.
L. H. Kendrick, Young Graphs: 1089 et al., J. Int. Seq. 18 (2015) 15.9.7.
N. J. A. Sloane, 2178 And All That, arXiv:1307.0453 [math.NT], 2013; Fib. Quart., 52 (2014), 99-120.
FORMULA
MATHEMATICA
Rest@Select[FromDigits /@ Tuples[{0, 198}, 11], IntegerDigits[4*#] == Reverse@IntegerDigits[#] &] (* Arkadiusz Wesolowski, Aug 14 2012 *)
okQ[t_]:=t==Reverse[t]&&First[t]!=0&&Min[Length/@Split[t]]>1; 198#&/@ Flatten[ Table[FromDigits/@Select[Tuples[{0, 1}, n], okQ], {n, 20}]] (* Harvey P. Dale, Jul 03 2013 *)
PROG
(PARI) rev(n) = (eval(concat(Vecrev(Str(n)))));
isok(n) = rev(n) == 4*n; \\ Michel Marcus, Sep 13 2015
CROSSREFS
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
Corrected and extended by David W. Wilson Aug 15 1996, Dec 15 1997
a(20)-a(21) from Arkadiusz Wesolowski, Aug 14 2012
STATUS
approved