

A151969


a(n) = smallest integer >= n which has only prime factors 2 and 5.


4



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, 32, 32, 32, 32, 32, 32, 32, 40, 40, 40, 40, 40, 40, 40, 40, 50, 50, 50, 50, 50, 50, 50, 50, 50, 50, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 80, 80, 80, 80, 80
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OFFSET

1,2


LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000


MATHEMATICA

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, upto1}]] (* The program uses the SelectFirst function from Mathematica version 10 *) (* Harvey P. Dale, Jan 28 2016 *)


PROG

(R) f < function(n) nextn(n, factors = c(2, 5))
a < matrix(1:256, ncol=1)
apply(a, 1, f)


CROSSREFS

Cf. A130916, A134361, A151970.
Sequence in context: A327625 A084824 A184615 * A261393 A327629 A121528
Adjacent sequences: A151966 A151967 A151968 * A151970 A151971 A151972


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Aug 23 2009


STATUS

approved



