OFFSET
1,1
COMMENTS
The sequence misses the primes.
When m is a term, then m = d*q + r and r<q<d are in geometric progression; but also, in this case, m = d'*q' + r with r<d'<q' that are in geometric progression with d'=q and q'=d (see examples). - Bernard Schott, May 15 2020
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
C. Hughes, Geometric Division
Wikipedia, Euclidean division
EXAMPLE
58 is in the sequence because 58 = 9*6 + 4, where 9, 6 and 4 are consecutive terms in a geometric sequence.
For a(4) = 58 with noninteger ratio = 3/2:
58 | 9 58 | 6
------ ------
4 | 6 4 | 9
For a(16) = 258 with integer ratio = 4:
258 | 32 258 | 8
------ -------
2 | 8 2 | 32
MATHEMATICA
mx = 1388; m = Ceiling @ Sqrt[mx]; s={}; Do[r = Select[Divisors[k^2], #<k &]; q = k^2/r; v = q * k + r; s = Join[s, v], {k, 1, m}]; Select[Union[s], # <= mx &] (* Amiram Eldar, Aug 28 2019 *)
PROG
(PARI) is(n)={for(d=1, n, if((n\d)*(n%d)==d^2, return(1))); return(0)}
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Nick Hobson, Jan 20 2007
STATUS
approved