

A351895


Numbers with an equal number of odd and even digits in their factorialbase representation.


2



2, 5, 25, 26, 29, 30, 34, 37, 38, 41, 42, 46, 51, 55, 56, 59, 63, 67, 68, 71, 73, 74, 77, 78, 82, 85, 86, 89, 90, 94, 99, 103, 104, 107, 111, 115, 116, 119, 723, 727, 728, 731, 735, 739, 740, 743, 745, 746, 749, 750, 754, 757, 758, 761, 762, 766, 771, 775, 776
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OFFSET

1,1


LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000
Wikipedia, Factorial number system.
Index entries for sequences related to factorial base representation.


EXAMPLE

5 is a term since its factorialbase representation, 21, has one odd digit, 1, and one even digit, 2.


MATHEMATICA

max = 7; fctBaseDigits[n_] := IntegerDigits[n, MixedRadix[Range[max, 2, 1]]]; Select[Range[1, max!], EvenQ[Length[(d = fctBaseDigits[#])]] && Count[d, _?EvenQ] == Length[d]/2 &]


CROSSREFS

Cf. A007623, A351893, A351894.
A138524 is a subsequence.
Similar sequences: A031443 (binary), A227870 (decimal).
Sequence in context: A120759 A326971 A000895 * A109306 A009560 A333591
Adjacent sequences: A351892 A351893 A351894 * A351896 A351897 A351898


KEYWORD

nonn,base


AUTHOR

Amiram Eldar, Feb 24 2022


STATUS

approved



