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 A080592 #20 Apr 29 2018 09:37:42
%S A080592 66,63,57,95
%N A080592 My school teacher gave it to me as a challenge. But he died last week and I do not have the answer.
%C A080592 From _Rick L. Shepherd_, Jun 28 2008: (Start)
%C A080592 The next (and last) term may be 79. Add the distinct digits used in each prime factor of the prime factorization (ignoring exponents) to get these sums: 6, 10, 13, 15, 16 (i.e., A141346(a(n))).
%C A080592 For example, 66 = 2*3*11 --> {1,2,3} --> 1+2+3=6. Observe that (*) A141346(a(n+1)) = A141346(a(n)) - n + 5. There are an infinite number of k such that A141346(k) = a(n) above, so what pattern selects specifically these?
%C A080592 Take a(1) = 66 arbitrarily (or maybe because this is the smallest composite repdigit number ddd... (A010785) such that A141346(ddd...)=d [and d is, well, *the* "perfect number" (A000396(1)) with which to start]).
%C A080592 Then for n >= 2 a(n+1) is, whenever possible, the largest positive integer less than a(n) such that (*) and otherwise the smallest integer greater than a(n) such that (*). (This pattern could actually be continued through a(11) without modification but then A141346(a(12)) would have the impossible requirement to be -5.
%C A080592 Also problematic is that A141346(a(6)) would be 16 also so the question arises whether to use < or <= above.) On the other hand, from such few terms this pattern is quite possibly just a coincidence -- the intended pattern may be something entirely different (and may depend upon knowing information beyond the numbers themselves such as numerical scores on tests, atomic numbers, ASCII codes, keypad configurations, languages, etc.). (End)
%F A080592 One possible formula: For n = 1..4, a(n) = 60 + (((-n^2+n+4)/2) + 9*floor(n/4))*(3+4*floor(n/4)). - _Wesley Ivan Hurt_, Jan 03 2013
%Y A080592 Cf. A141346.
%K A080592 nonn,unkn
%O A080592 1,1
%A A080592 DexXx (dexx(AT)pop.com.br), Feb 22 2003