cp's OEIS Frontend

A108571 Any digit d in the sequence says: "I am part of an integer in which you'll find d digits d".

%I A108571 #45 Oct 18 2022 01:30:11
%S A108571 1,22,122,212,221,333,1333,3133,3313,3331,4444,14444,22333,23233,
%T A108571 23323,23332,32233,32323,32332,33223,33232,33322,41444,44144,44414,
%U A108571 44441,55555,122333,123233,123323,123332,132233,132323,132332,133223,133232,133322,155555
%N A108571 Any digit d in the sequence says: "I am part of an integer in which you'll find d digits d".
%C A108571 The sequence is finite. Last term: 999999999888888887777777666666555554444333221.
%C A108571 Number of terms is 66712890763701234740813164553708284. - _Zak Seidov_, Jan 02 2007
%C A108571 Fixed points of A139337. - _Reinhard Zumkeller_, Apr 14 2008
%C A108571 Sequence contains squares (A181392) and cubes (A225886^3) but no higher powers, see Comments in A181392. - _Giovanni Resta_, May 19 2013
%H A108571 T. D. Noe, <a href="/A108571/b108571.txt">Table of n, a(n) for n=1..21056</a> (terms < 10^10)
%H A108571 Michael S. Branicky, <a href="/A108571/a108571.py.txt">Python program</a>
%e A108571 23323 is in the sequence because it has two 2's and three 3's.
%e A108571 23332 is in the sequence because it has two 2's and three 3's.
%e A108571 23333 is not in the sequence because it has only one 2 and four 3's.
%o A108571 (PARI) is(n)={ vecmin(n=vecsort(digits(n))) && #n==normlp(Set(n),1) && !for(i=1,#n, n[i+n[i]-1]==n[i] || return; i+n[i]>#n || n[i+n[i]]>n[i] || return; n[i]>1 && i+=n[i]-1)} \\ _M. F. Hasler_, Sep 22 2014
%o A108571 (Python) # see link for a function that directly generates terms
%o A108571 def ok(n): s = str(n); return all(s.count(d) == int(d) for d in set(s))
%o A108571 def aupto(limit): return [m for m in range(1, limit+1) if ok(m)]
%o A108571 print(aupto(155555)) # _Michael S. Branicky_, Jan 22 2021
%Y A108571 Cf. A127007, A139337, A078348 (subsequence of primes), A181392, A225886.
%K A108571 base,easy,fini,nonn
%O A108571 1,2
%A A108571 _Eric Angelini_, Jul 05 2005