A091677 - OEIS

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).

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

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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