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 A375242 #14 Aug 16 2024 23:14:11
%S A375242 2,4,5,7,8,11,13,14,16,17,20,22,23,25,26,29,31,32,34,35,38,40,41,43,
%T A375242 44,47,49,50,52,53,56,58,59,61,62,65,67,68,70,71,74,76,77,79,80,83,85,
%U A375242 86,88,89,92,94,95,97,98,101,103,104,106,107,110,112,113,115,116
%N A375242 Numbers with digital root in {2, 4, 5, 7, 8}.
%C A375242 Also nontriangular numbers with digital root in {2, 4, 5, 7, 8}.
%D A375242 Albert H. Beiler, Recreations in the theory of numbers, New York, Dover, (2nd ed.) 1966. See p. 190.
%H A375242 Stefano Spezia, <a href="/A375242/b375242.txt">Table of n, a(n) for n = 1..10000</a>
%H A375242 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,1,-1).
%F A375242 G.f.: x*(2 + 2x + x^2 + 2*x^3 + x^4 + x^5)/((1 - x)^2*(1 + x + x^2 + x^3 + x^4)).
%F A375242 a(n) ~ 9*n/5.
%t A375242 A010888[n_]:=If[n>0,n - 9*Floor[(n-1)/9],0]; Select[Range[0,130], MemberQ[{2,4,5,7,8},A010888[#]] &]
%o A375242 (PARI) list(lim)=my(v=List()); forstep(n=2,lim\1,[2, 1, 2, 1, 3], listput(v,n)); Vec(v) \\ _Charles R Greathouse IV_, Aug 07 2024
%o A375242 (PARI) is(n)=!setsearch([0,1,3,6],n%9) \\ _Charles R Greathouse IV_, Aug 07 2024
%Y A375242 Complement of A055264. Complement of A375241 in A014132.
%Y A375242 Cf. A010888.
%K A375242 nonn,base,easy
%O A375242 1,1
%A A375242 _Stefano Spezia_, Aug 07 2024