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A356369 Numbers such that each digit "d" occurs d times, for every digit from 1 to the largest digit. 1

%I #45 Nov 12 2022 10:21:12

%S 1,122,212,221,122333,123233,123323,123332,132233,132323,132332,

%T 133223,133232,133322,212333,213233,213323,213332,221333,223133,

%U 223313,223331,231233,231323,231332,232133,232313,232331,233123,233132,233213,233231,233312,233321,312233,312323

%N Numbers such that each digit "d" occurs d times, for every digit from 1 to the largest digit.

%C A version of self-describing integers (cf. A105776).

%C The sequence is finite.

%C The last term is 999999999888888887777777666666555554444333221.

%C This sequence contains Sum_{m = 1..9} Product_{k = 1..m} binomial( k*(k+1)/2, k) = 65191584768311709900058498136517664 terms. - _Thomas Scheuerle_ and _David A. Corneth_, Oct 17 2022

%H Michael S. Branicky, <a href="/A356369/b356369.txt">Table of n, a(n) for n = 1..10000</a>

%e 213323 is a term because the digit 1 occurs once, the digit 2 twice and 3 three times. Every digit from 1 to 3 is present.

%o (Python)

%o from itertools import islice

%o from sympy.utilities.iterables import multiset_permutations

%o def agen():

%o for m in range(1, 10):

%o s = "".join(str(k)*k for k in range(1, m+1))

%o yield from (int("".join(p)) for p in multiset_permutations(s))

%o print(list(islice(agen(), 65))) # _Michael S. Branicky_, Oct 17 2022

%Y Cf. A105776, A108571, A247700.

%K nonn,base,fini

%O 1,2

%A _Marc Morgenegg_, Oct 17 2022

%E Corrected by and more terms from _David A. Corneth_, Oct 17 2022

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Last modified July 25 23:06 EDT 2024. Contains 374615 sequences. (Running on oeis4.)