A255341 Numbers n such that there is exactly one 1 in their factorial base representation (A007623).

1, 2, 5, 6, 10, 13, 14, 17, 19, 20, 23, 24, 28, 36, 40, 42, 46, 49, 50, 53, 54, 58, 61, 62, 65, 67, 68, 71, 73, 74, 77, 78, 82, 85, 86, 89, 91, 92, 95, 97, 98, 101, 102, 106, 109, 110, 113, 115, 116, 119, 120, 124, 132, 136, 138, 142, 168, 172, 180, 184, 186, 190, 192, 196, 204, 208, 210

Offset: 1

Author

Antti Karttunen, Apr 27 2015

Keywords

• nonn
• base

Examples

			The factorial base representation (A007623) of 5 is "21", which contains exactly one 1, thus 5 is included in the sequence.
The f.b.r. of 23 is "321", with only one 1, thus 23 is included in the sequence.
The f.b.r. of 24 is "1000", with only one 1, thus 24 is included in the sequence.
		

Links

• Antti Karttunen, Table of n, a(n) for n = 1..13069

Crossrefs

Cf. A007623, A257511, A255411, A255342, A255343.

Subsequence of A256450.

Subsequences: A000142, A033312 (apart from its zero-terms).

Programs

Mathematica

factBaseIntDs[n_] := Module[{m, i, len, dList, currDigit}, i = 1; While[n > i!, i++]; m = n; len = i; dList = Table[0, {len}]; Do[currDigit = 0; While[m >= j!, m = m - j!; currDigit++]; dList[[len - j + 1]] = currDigit, {j, i, 1, -1}]; If[dList[[1]] == 0, dList = Drop[dList, 1]]; dList]; s = Table[FromDigits[factBaseIntDs[n]], {n, 210}]; {0}~Join~Flatten@ Position[s, x_ /; DigitCount[x][[1]] == 1] (* Michael De Vlieger, Apr 27 2015, after Alonso del Arte at A007623 *)