OFFSET
1,2
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
Sum_{n>=1} 1/a(n) = (5*10)/((5-1)*(10-1)) = 25/18. - Amiram Eldar, Sep 25 2020
a(n) ~ exp(sqrt(2*log(5)*log(10)*n)) / sqrt(50). - Vaclav Kotesovec, Sep 25 2020
MAPLE
N:= 10^8: # for all terms <= N
sort([seq(seq(5^i*10^j, j=0..floor(log[10](N/5^i))), i=0..floor(log[5](N)))]); # Robert Israel, Nov 19 2019
MATHEMATICA
Block[{a = 5, b = 10, n = 10^7}, Sort@ Flatten@ Table[a^p * b^q, {p, 0, Log[a, n]}, {q, 0, Log[b, n/(a^p)]}]] (* Michael De Vlieger, Nov 19 2019 *)
PROG
(PARI) list(lim)=my(v=List(), N); for(n=0, logint(lim\=1, 10), N=10^n; while(N<=lim, listput(v, N); N*=5)); Set(v) \\ Charles R Greathouse IV, Jan 10 2018
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
STATUS
approved