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 A151969 #4 Jan 28 2016 09:52:49 %S A151969 1,2,4,4,5,8,8,8,10,10,16,16,16,16,16,16,20,20,20,20,25,25,25,25,25, %T A151969 32,32,32,32,32,32,32,40,40,40,40,40,40,40,40,50,50,50,50,50,50,50,50, %U A151969 50,50,64,64,64,64,64,64,64,64,64,64,64,64,64,64,80,80,80,80,80 %N A151969 a(n) = smallest integer >= n which has only prime factors 2 and 5. %H A151969 Harvey P. Dale, <a href="/A151969/b151969.txt">Table of n, a(n) for n = 1..1000</a> %t A151969 Module[{upto=100,pwr,f25},pwr=Ceiling[Log[2,upto]];f25=Select[ Sort[ Flatten[ Table[Times@@@Union[Sort/@Tuples[{2,5},n]],{n,0,pwr}]]],#<= upto&]; Table[SelectFirst[f25,#>i&],{i,0,upto-1}]] (* The program uses the SelectFirst function from Mathematica version 10 *) (* _Harvey P. Dale_, Jan 28 2016 *) %o A151969 (R) f <- function(n) nextn(n, factors = c(2,5)) %o A151969 a <- matrix(1:256,ncol=1) %o A151969 apply(a,1,f) %Y A151969 Cf. A130916, A134361, A151970. %K A151969 nonn %O A151969 1,2 %A A151969 _N. J. A. Sloane_, Aug 23 2009