

A300018


For any k, the cumulative sum a(1) + a(2) + a(3) + ... + a(k) shows at least a digit 4.


1



4, 10, 20, 6, 1, 2, 3, 8, 30, 40, 16, 5, 9, 50, 36, 7, 17, 60, 18, 12, 46, 11, 13, 14, 15, 19, 21, 31, 22, 28, 66, 24, 70, 80, 26, 34, 67, 23, 76, 44, 56, 54, 47, 33, 68, 32, 27, 25, 29, 35, 51, 43, 57, 53, 48, 42, 58, 52, 49, 41, 59, 61, 37, 63, 38, 62, 39, 64, 45, 72, 90, 100, 110, 116, 74
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OFFSET

1,1


COMMENTS

The sequence starts with a(1) = 4 and is always extended with the smallest integer not yet present that does not lead to a contradiction.
A permutation of the natural numbers.


LINKS

JeanMarc Falcoz, Table of n, a(n) for n = 1..10001


EXAMPLE

4 shows a digit 4, of course (k = 1)
4 + 10 = 14 and 14 shows at least a digit 4 (k = 2)
4 + 10 + 20 = 34 and 34 shows at least a digit 4 (k = 3)
4 + 10 + 20 + 6 = 40 and 40 shows at least a digit 4 (k = 4)
4 + 10 + 20 + 6 + 1 = 41 and 41 shows at least a digit 4 (k = 5)
4 + 10 + 20 + 6 + 1 + 2 = 43 and 43 shows at least a digit 4 (k = 6)
...


CROSSREFS

Cf. A300015 (which is the lexicographic first sequence of positive integers without duplicate terms having this property).
Sequence in context: A155383 A155229 A155220 * A268221 A086176 A015789
Adjacent sequences: A300015 A300016 A300017 * A300019 A300020 A300021


KEYWORD

nonn,base


AUTHOR

Eric Angelini and JeanMarc Falcoz, Feb 23 2018


STATUS

approved



