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A242491 Numbers avoiding subtractive notation when written in Roman numerals. 0
1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18, 20, 21, 22, 23, 25, 26, 27, 28, 30, 31, 32, 33, 35, 36, 37, 38, 50, 51, 52, 53, 55, 56, 57, 58, 60, 61, 62, 63, 65, 66, 67, 68, 70, 71, 72, 73, 75, 76, 77, 78, 80, 81, 82, 83, 85, 86, 87, 88, 100, 101, 102, 103, 105 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numbers with only digits 0,1,2,3,5,6,7,8.

So this is a subsequence of A039145 with same number of 4 and 9: zero. - Michel Marcus, May 17 2014

LINKS

Table of n, a(n) for n=1..68.

EXAMPLE

4 in Roman numerals is IV (5 - 1) and so 4 is not in this sequence.

PROG

(PARI) isok(n) = my(v = vecsort(digits(n))); ! (vecsearch(v, 4) || vecsearch(v, 9)); \\ Michel Marcus, May 19 2014

CROSSREFS

Sequence in context: A184514 A001068 A039145 * A038129 A062071 A087069

Adjacent sequences:  A242488 A242489 A242490 * A242492 A242493 A242494

KEYWORD

nonn,base,easy

AUTHOR

J. Lowell, May 16 2014

STATUS

approved

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Last modified August 24 03:51 EDT 2019. Contains 326260 sequences. (Running on oeis4.)