This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A288352 #21 Jun 12 2017 08:33:57 %S A288352 0,0,5,168,659,163,14,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, %T A288352 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, %U A288352 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 %N A288352 Number of strings of n digits from 1..9 such that a formula using the single digits in the given order with result 0 needs at least one division. %C A288352 For definitions see A288350. An exhaustive computation for the 9^8 strings of 8 digits confirms that for all of them formulas avoiding divisions exist. a(8) = 0 implies that a(n) = 0 for n > 8. %e A288352 a(3)=5, because the 5 3-digit strings 263 (0=2-6/3), 284 (0=2-8/4), 362 (0=3-6/2), 393 (3-9/3), 482 (0=4-8/2) are the only ones of the 9^3-A288351(3)=274 3-digit strings for which a formula with result 0 exists that cannot avoid including a division. %e A288352 A288502 provides a list of all strings with this property. %Y A288352 Cf. A288350, A288351, A288502, A288550. %K A288352 nonn %O A288352 1,3 %A A288352 _Hugo Pfoertner_, Jun 10 2017