OFFSET
1,1
COMMENTS
Powers of 2 are excluded. If they are included we get A328092.
LINKS
P. Korus (Proposer), A slow shuffle, Problem 12008, Amer. Math. Monthly, 126 (No. 8, 2019), pp. 756-759.
MAPLE
isA328091 := proc(n)
local kl, k, l, m, d ;
# kl is k+l
for kl from 0 do
# 2^k<=2n, 2^(k-1)<=n, k-1 <=log2(n), k<=log2(n)+1 and l<k, so k+l<=2*log2(n)+2
if kl > 2*ilog2(n)+2 then
return false ;
end if;
# kl=l+k, l < k
for k from floor(kl/2) to kl do
l := kl-k ;
if l < k and l >= 0 then
for m from 0 to k-1 do
d := (2^(kl+2)-2^(l+1)+1) / (2^(l+m+3)-2^(m+2)+1) ;
if type (d, 'integer') and n = 2^m*d then
return true ;
end if;
end do:
end if:
end do:
end do:
end proc:
for n from 2 do
if isA328091(n) then
print(n) ;
end if;
end do: # R. J. Mathar, Feb 06 2025
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Oct 17 2019
EXTENSIONS
Extended to 20 terms by R. J. Mathar, Feb 06 2025
STATUS
approved