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 A178356 #20 Jul 05 2022 11:31:00
%S A178356 0,1,2,3,5,8,21,987
%N A178356 Fibonacci numbers whose successive digits decrease by 1.
%C A178356 Only need to consider the Fibonacci numbers less than 9876543210.
%F A178356 { A000045 } intersect { A138142 }. - _Alois P. Heinz_, Jul 05 2022
%t A178356 Join[{0,1,2,3,5,8},Select[Fibonacci[Range[250]],Union[Differences[ IntegerDigits[#]]]=={-1}&]] (* _Harvey P. Dale_, Sep 14 2011 *)
%o A178356 (PARI) n=0;while((f=fibonacci(n))<=9876543210,if(is(f),print1(f", "));n++) \\ _Charles R Greathouse IV_, Sep 14 2011
%Y A178356 Cf. A000045, A138142, A178355.
%K A178356 nonn,base,fini,full
%O A178356 1,3
%A A178356 _Felix Tubiana_, May 25 2010
%E A178356 Definition clarified by _Harvey P. Dale_, Sep 14 2011