A236403 - OEIS

%I #21 Dec 31 2021 09:53:59

%S 11,12,13,14,15,16,17,18,19,21,22,23,24,25,26,27,28,29,31,32,33,34,35,

%T 36,37,38,39,41,42,43,44,45,46,47,48,49,51,52,53,54,55,56,57,58,59,61,

%U 62,63,64,65,66,67,68,69,71,72,73,74,75,76,77,78,79,81,82,83,84,85,86,87,88,89,91,92,93,94,95,96,97,98,99,110,111,112,113,114,115,116,117,118,119

%N Numbers not in A236402.

%C This sequence has density 0, since all numbers except a thin fraction have digits 0 through 18 in base 100. In particular, there are at most x^0.99782 members up to x for large enough x. (This can be improved.) - _Charles R Greathouse IV_, Jan 30 2014

%C Where does this first differ from A038687? - _R. J. Mathar_, Feb 03 2014

%C Is this a shifted version of A031954? - _R. J. Mathar_, Feb 03 2014

%o (PARI) is(n)=my(d=digits(n), S=Set(d), v=List()); for(i=2, #d, listput(v, 10*d[i-1]+d[i])); S=setunion(S,Set(v)); for(i=2, #d, if(!setsearch(S, d[i-1]+d[i]), return(1))); 0 \\ _Charles R Greathouse IV_, Mar 10 2021

%o (Python)

%o def ok(n):

%o   s = str(n)

%o   return not all(str(sum(map(int, s[i:i+2]))) in s for i in range(len(s)-1))

%o print(list(filter(ok, range(120)))) # _Michael S. Branicky_, Jun 11 2021

%Y Subsequence of A052382.

%Y Cf. A236402.

%K nonn,base

%O 1,1

%A _Eric Angelini_, Jan 30 2014

%E Missing a(82) added by _Charles R Greathouse IV_, Mar 10 2021