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 A152493 #8 Jun 10 2025 01:30:52
%S A152493 0,1,2,3,4,5,6,7,9,10,12,16,17,18,30,37,58
%N A152493 Numbers k such that the decimal expansion of 2^k+5^k contains no 0's (probably 58 is last term).
%e A152493 {n,2^n+5^n}: {0,2}, {1,7}, {2,29}, {3,133}, {4,641}, {5,3157}, {6,15689}, {7,78253}, {9,1953637}, {10,9766649}, {12,244144721}, {16,152587956161}, {17,762939584197}, {18,3814697527769}, {30,931322574616552257449}, {37,72759576141834396472156597}, {58,34694469519536141888238777858214286477369}.
%t A152493 Do[p=2^n+5^n;If[FreeQ[IntegerDigits[p],0],Print[{n,p}]],{n,0,2000}]
%t A152493 Select[Range[0,10000],DigitCount[2^#+5^#,10,0]==0&] (* _Harvey P. Dale_, Oct 14 2011 *)
%Y A152493 Cf. A074600, A007496.
%K A152493 base,nonn
%O A152493 0,3
%A A152493 _Zak Seidov_, Oct 25 2009