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A231880 The digits of a(n) and a(n+1) together can be reordered to form a square; lexicographically earliest sequence of distinct nonnegative integers with this property. 7
0, 10, 24, 3, 6, 1, 8, 14, 4, 9, 16, 12, 15, 21, 25, 2, 5, 22, 45, 18, 28, 81, 34, 20, 29, 7, 48, 13, 27, 19, 26, 11, 52, 30, 42, 39, 61, 33, 46, 17, 23, 40, 32, 49, 60, 57, 64, 35, 92, 43, 36, 31, 63, 54, 67, 41, 38, 44, 62, 47, 56, 70, 65, 74, 124, 69, 37 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

A231880 and A231881 eventually merge: A231880(2540) = 2536; A231881(2539) = 2541; A231880(2541,2542,..) = A231881(2540,2541,..) = 2544,2551; ... Hans Havermann, Nov 17 2013

LINKS

Hans Havermann, Table of n, a(n) for n = 0..10000

MATHEMATICA

a[0] = 0; a[n_] := a[n] = Block[{k = 1, idm = IntegerDigits@ a[n - 1], t = a@# & /@ Range[n - 1]}, Label[ start]; While[ MemberQ[t, k], k++]; While[ Select[ Permutations[ Join[idm, IntegerDigits[ k]]], #[[1]] != 0 && IntegerQ[ Sqrt[ FromDigits[ #]]] &] == {}, k++; Goto[ start]]; k]; Array[a, 100, 0] (* Robert G. Wilson v, Nov 17 2013 *)

CROSSREFS

A variant of A228407. Cf. A231881.

Sequence in context: A177126 A300150 A187621 * A102089 A250797 A250583

Adjacent sequences:  A231877 A231878 A231879 * A231881 A231882 A231883

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane, Nov 17 2013, based on a posting to the Sequence Fans Mailing List by Andrew Weimholt, Nov 12 2013

EXTENSIONS

Corrected and extended by Hans Havermann, Nov 17 2013

More terms added (from b-file) by Jon E. Schoenfield, Dec 22 2013

STATUS

approved

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Last modified October 16 11:39 EDT 2021. Contains 348041 sequences. (Running on oeis4.)