login
Numbers k whose factorial base representation A007623(k) does not contain any nonleading zeros.
15

%I #37 Jan 24 2024 01:49:29

%S 1,3,5,9,11,15,17,21,23,33,35,39,41,45,47,57,59,63,65,69,71,81,83,87,

%T 89,93,95,105,107,111,113,117,119,153,155,159,161,165,167,177,179,183,

%U 185,189,191,201,203,207,209,213,215,225,227,231,233,237,239,273

%N Numbers k whose factorial base representation A007623(k) does not contain any nonleading zeros.

%C a(A003422(n)) = A007489(n).

%C a(A007489(n)) = (n+1)!-1 thus A007489(n) gives the number of terms less than (n+1)! in this sequence.

%C Equivalently, there are n! terms in the sequence with their magnitude in range n!..(n+1)!.

%C Also numbers k such that A304036(k) = 1 for k > 0. - _Seiichi Manyama_, May 06 2018

%H Seiichi Manyama, <a href="/A227157/b227157.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..5913 from Antti Karttunen)

%t q[n_] := Module[{k = n, m = 2, c = 0, r}, While[{k, r} = QuotientRemainder[k, m]; k != 0 || r != 0, If[r == 0, c++]; m++]; c == 0]; Select[Range[300], q] (* _Amiram Eldar_, Jan 23 2024 *)

%o (Scheme, with _Antti Karttunen_'s IntSeq-library): (define A227157 (NONZERO-POS 1 1 A208575))

%Y The sequence gives all n for which A208575(n) is not zero. Complement of A227187. Subsets: A071156 (apart from zero), A231716, A231720.

%Y Cf. also A003422, A007489, A007623, A153880, A227130, A227132, A304036.

%K nonn,base

%O 1,2

%A _Antti Karttunen_, Jul 04 2013