A261415 - OEIS

A261415

The maximal midpoint-free set Z_7^{+}{0,1,3}.

0, 1, 3, 7, 8, 10, 21, 22, 24, 49, 50, 52, 56, 57, 59, 70, 71, 73, 147, 148, 150, 154, 155, 157, 168, 169, 171, 343, 344, 346, 350, 351, 353, 364, 365, 367, 392, 393, 395, 399, 400, 402, 413, 414, 416, 490, 491, 493, 497, 498, 500, 511, 512, 514

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OFFSET

1,3

COMMENTS

The sequence consists of the numbers that expressed in base 7 contain only the digits 0, 1 and 3. - Giovanni Resta, Aug 26 2015

LINKS

Table of n, a(n) for n=1..54.

Roger B. Eggleton, Maximal Midpoint-Free Subsets of Integers, International Journal of Combinatorics, Volume 2015, Article ID 216475, 14 pages.

Index entries for 7-automatic sequences.

MATHEMATICA

Select[Range[0, 1000], Union[ IntegerDigits[#, 7], {0, 1, 3}] == {0, 1, 3} &] (* Giovanni Resta, Aug 26 2015 *)

PROG

(PARI) is(n)=#setunion(Set(digits(n, 7)), [0, 1, 3])==3 \\ Charles R Greathouse IV, Feb 15 2017

CROSSREFS

Sequence in context: A316493 A213650 A283759 * A331547 A285164 A106753

Adjacent sequences: A261412 A261413 A261414 * A261416 A261417 A261418

KEYWORD

nonn,base,easy

AUTHOR

N. J. A. Sloane, Aug 25 2015

EXTENSIONS

More terms from Giovanni Resta, Aug 26 2015

STATUS

approved