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A256406 Numbers n such that for some m, A166133(m)=n, A166133(m+1)=n^2-1, in order of increasing m. 3
3, 198, 270, 570, 522, 600, 822, 882, 1062, 2130, 1950, 2592, 2268, 2310, 3168, 2970, 5502, 6702, 5022, 7350, 10038, 10428, 10500, 9438, 14562, 14010, 15288, 17028, 18060, 19698, 17958, 19890, 18522, 20772, 29670, 20550, 22158, 16650 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

In other words, the next term in A166133 after n is as large as it can be. Terms are listed in order of appearance in A166133.

With the exception of the initial 3, the terms appear to be a (permuted) subset of A014574; i.e. the divisors of a(n)^2-1 are 1, a(n)-1, a(n)+1, and a(n)^2-1. - Hans Havermann, Apr 03 2015

See the "blog" file in A166133 for discussion.

LINKS

Hans Havermann and John Mason, Table of n, a(n) for n = 1..6575  [Terms 1 through 480 were computed by Hans Havermann; terms 481 through 6575 by John Mason, Apr 05 2015]

PROG

(Haskell)

a256406 n = a256406_list !! (n-1)

a256406_list = f a166133_list where

   f (u:vs'@(v:ws)) | u > v || v /= u ^ 2 - 1 = f vs'

                    | otherwise               = u : f ws

-- Reinhard Zumkeller, Apr 01 2015

CROSSREFS

Cf. A014574, A166133, A256407 (sorted version).

Sequence in context: A209120 A336250 A256407 * A157565 A157598 A023310

Adjacent sequences:  A256403 A256404 A256405 * A256407 A256408 A256409

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Apr 01 2015, based on a comment of Franklin T. Adams-Watters in A166133.

STATUS

approved

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Last modified August 11 11:29 EDT 2022. Contains 356065 sequences. (Running on oeis4.)