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A075420
Trajectory of n under the Reverse and Add! operation carried out in base 4 (presumably) does not reach a palindrome.
9
290, 318, 378, 381, 438, 444, 462, 498, 501, 504, 510, 545, 567, 573, 627, 633, 636, 639, 693, 696, 699, 717, 719, 732, 751, 753, 756, 759, 765, 775, 795, 799, 800, 822, 823, 828, 835, 847, 859, 882, 883, 888, 894, 895, 915, 919, 927, 948, 954, 967, 972
OFFSET
1,1
COMMENTS
Base-4 analog of A023108 (base 10) and A066059 (base 2).
MATHEMATICA
limit = 10^3; (* Assumes that there is no palindrome if none is found before "limit" iterations *)
Select[Range[1000],
Length@NestWhileList[# + IntegerReverse[#, 4] &, #, # !=
IntegerReverse[#, 4] &, 1, limit] == limit + 1 &] (* Robert Price, Oct 16 2019 *)
PROG
(PARI) {stop=1000; for(n=1, 980, k=n; c=0; while(c<stop, a=k; rev=0; while(a>0, d=divrem(a, 4); a=d[1]; rev=4*rev+d[2]); if(rev==k, c=stop+1, k=k+rev; c++)); if(c==stop, print1(n, ", ")))}
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Klaus Brockhaus, Sep 18 2002
EXTENSIONS
Offset changed to 1 by A.H.M. Smeets, Feb 10 2019
STATUS
approved