A222815 Numbers (not ending in 0) which are 4 times their digit-reversal.

8712, 87912, 879912, 8799912, 87128712, 87999912, 871208712, 879999912, 8712008712, 8791287912, 8799999912, 87120008712, 87912087912, 87999999912, 871200008712, 871287128712, 879120087912, 879912879912, 879999999912, 8712000008712, 8712879128712, 8791200087912

Offset: 1

Author

N. J. A. Sloane, Mar 11 2013

Keywords

• nonn
• base

Comments

There are Fibonacci(floor((n-2)/2)) terms with n digits (this is essentially A103609). - Ray Chandler, Oct 12 2017

Links

• Ray Chandler, Table of n, a(n) for n = 1..10000
• N. J. A. Sloane, 2178 And All That, Fib. Quart., 52 (2014), 99-120.
• N. J. A. Sloane, 2178 And All That [Local copy]

Crossrefs

Equals 4*A008918.

Programs

Mathematica

okQ[t_]:=t==Reverse[t]&&First[t]!=0&&Min[Length/@Split[t]]>1; Sort[Flatten[ (4*198)#&/@Flatten[Table[FromDigits/@Select[Tuples[{0,1},n],okQ],{n,12}]]]] (* Harvey P. Dale, Jul 03 2013 *)