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A092212 a(n) = smallest non-palindromic k such that the base-2 Reverse and Add! trajectory of k is palindrome-free and joins the trajectory of A092210(n). 2
26, 65649, 89, 4193, 3599, 775, 68076, 2173 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Terms a(9) to a(29) are 205796147 (conjectured), 4402, 16720, 1089448, 442, 537, unknown, 1050177, 1575, 28822, unknown, 40573, 1066, 1587, unknown, unknown, 1081, 1082, 1085, 1115, 4185.
a(n) >= A092210(n); a(n) = A092210(n) iff the trajectory of A092210(n) is palindrome-free, i.e., A092210(n) is also a term of A075252.
a(n) determines a 1-to-1 mapping from the terms of A092210 to the terms of A075252, the inverse of the mapping determined by A092211.
The 1-to-1 property of the mapping depends on the conjecture that the base-2 Reverse and Add! trajectory of each term of A092210 contains only a finite number of palindromes (cf. A092215).
Base-2 analog of A089494 (base 10) and A091677 (base 4).
LINKS
EXAMPLE
A092210(3) = 64, the trajectory of 64 joins the trajectory of 89 at 48480, so a(3) = 89. A092210(5) = 98, the trajectory of 98 joins the trajectory of 3599 = A075252(16) at 401104704, so a(5) = 3599.
MATHEMATICA
limit = 10^3; (* Assumes that there is no palindrome if none is found before "limit" iterations *)
utraj = NestList[# + IntegerReverse[#, 2] &, 1, limit];
A092210 = Flatten@{1, Select[Range[2, 266], (l =
Length@NestWhileList[# + IntegerReverse[#, 2] &, #, !
MemberQ[utraj, #] &, 1, limit];
utraj =
Union[utraj, NestList[# + IntegerReverse[#, 2] &, #, limit]];
l == limit + 1) &]};
A092212 = {};
For[i = 1, i <= Length@A092210, i++,
k = A092210[[i]];
itraj = NestList[# + IntegerReverse[#, 2] &, A092210[[i]], limit];
While[ktraj =
NestWhileList[# + IntegerReverse[#, 2] &,
k, # != IntegerReverse[#, 2] &, 1, limit];
PalindromeQ[k] || Length@ktraj != limit + 1 || ! IntersectingQ[itraj, ktraj], k++];
AppendTo[A092212, k]]; A092212 (* Robert Price, Nov 03 2019 *)
CROSSREFS
Sequence in context: A302396 A208186 A316677 * A365983 A265959 A112946
KEYWORD
nonn,base,more
AUTHOR
Klaus Brockhaus, Feb 25 2004
EXTENSIONS
a(1) and a(3) corrected by Robert Price, Nov 06 2019
STATUS
approved

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Last modified May 26 21:09 EDT 2024. Contains 372844 sequences. (Running on oeis4.)