OFFSET
1,3
COMMENTS
It appears that this is also the sequence of numbers with a record number of divisors all of whose prime factors are of the form 3k + 1. - Amiram Eldar, Sep 12 2019 [This is correct, see A343771. - Jianing Song, May 19 2021]
Indices of records of A004016. Apart from the first term, also indices of records of A002324. - Jianing Song, May 20 2021
LINKS
Jianing Song, Table of n, a(n) for n = 1..247 (all terms <= 10^75.)
EXAMPLE
a(2)=7 because a circle with radius sqrt(7) around the lattice point at (0,0) is the first circle that passes through more lattice points than a circle with radius 1, which passes through 6 points. The 12 hit points are (+-1/2,+-3*sqrt(3)/2), (+-2,+-sqrt(3)), (+-5/2, +-sqrt(3)/2).
PROG
(PARI) my(v=list_A344473(10^15), rec=0); print1(0, ", "); for(n=1, #v, if(numdiv(v[n])>rec, rec=numdiv(v[n]); print1(v[n], ", "))) \\ Jianing Song, May 20 2021, see program for A344473
CROSSREFS
Cf. A003136 (all occurring squared radii), A198799 (common terms), A230656 (index positions of records), A344472 (records).
Apart from the first term, subsequence of A343771.
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Oct 27 2013
EXTENSIONS
Offset corrected by Jianing Song, May 20 2021
STATUS
approved