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A091677 a(n) = smallest non-palindromic k such that the base-4 Reverse and Add! trajectory of k is palindrome-free and joins the trajectory of A091675(n). 2
469892287, 318, 68346, 66349, 269237759, 272353, 110333, 1082314, 4279, 3903, 1049659, 290, 1210, 4334, 275436, 4199, 73784, 2082046, 5046, 4212653, 1052467, 4768988414, 1073998008, 1051069, 1058784, 719, 795, 799, 265038, 119810013 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(1), a(5), a(22), a(23) and a(30) are conjectural; it is not yet ensured that they are minimal.

a(n) >= A091675(n); a(n) = A091675(n) iff the trajectory of A091675(n) is palindrome-free, i.e., A091675(n) is also a term of A075421.

a(n) determines a 1-1-mapping from the terms of A091675 to the terms of A075421, the inverse of the mapping determined by A091676.

The 1-1 property of the mapping depends on the conjecture that the base-4 Reverse and Add! trajectory of each term of A091675 contains only a finite number of palindromes (cf. A091680).

Base-4 analog of A089494.

LINKS

Table of n, a(n) for n=1..30.

Index entries for sequences related to Reverse and Add!

EXAMPLE

A091675(2) = 3, the trajectory of 3 joins the trajectory of 318 = A075421(2) at 20966400, so a(2) = 318. A091675(4) = 22, the trajectory of 22 joins the trajectory of 66349 = A075421(130) at 600785, so a(4) = 66349.

CROSSREFS

Cf. A075421, A091675, A091676, A091680, A089494.

Sequence in context: A323653 A246548 A260524 * A147717 A127888 A072232

Adjacent sequences:  A091674 A091675 A091676 * A091678 A091679 A091680

KEYWORD

nonn,base

AUTHOR

Klaus Brockhaus, Jan 28 2004

STATUS

approved

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Last modified August 3 14:40 EDT 2021. Contains 346438 sequences. (Running on oeis4.)