A326307 - OEIS

%I #33 May 20 2021 22:57:25

%S 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,2,2,1,

%T 1,1,1,1,1,1,1,2,2,2,1,1,1,1,1,1,1,2,2,2,2,1,1,1,1,1,1,2,2,2,2,2,1,1,

%U 1,1,1,2,2,2,2,2,2,1,1,1,1,2,2,2,2,2,2,2

%N a(n) is the index of n in the ordered list of the numbers with the same digits as n.

%C Ordinal transform of A328447.

%H David A. Corneth, <a href="/A326307/b326307.txt">Table of n, a(n) for n = 0..9999</a>

%H David A. Corneth, <a href="/A326307/a326307.gp.txt">PARI program</a>

%F a(A179239(n)) = 1.

%F a(10+n) = A007953(9*n)/9 (A007953 = sum of digits) for 0 < n < 91, but a(101) = 1 while A007953(9*91)/9 = 2. - _M. F. Hasler_, May 19 2021

%e a(321) = 6 as 321 is the sixth number made of the digits [1, 2, 3]. The five smaller numbers having these digits are 123, 132, 213, 231, 312.

%o (PARI) see Corneth link

%o (PARI) { o = vector(100); for (n=0, 87, print1 (o[1+fromdigits(vecsort(digits(n,base=10),,4),base)]++ ", ")) } \\ _Rémy Sigrist_, Oct 17 2019

%o (PARI) A326307(n,D=Vecsmall(digits(n)),c=1)={forperm(vecsort(D),d, d==D&&break; d[1]&&c++);c} \\ _M. F. Hasler_, May 19 2021

%Y Cf. A179239, A254524, A328447.

%K nonn,base,easy,look

%O 0,22

%A _David A. Corneth_, Oct 17 2019

%E Edited by _N. J. A. Sloane_, Oct 24 2019