OFFSET
1,1
COMMENTS
Given n > 4, n^2 + 1 is in the sequence. In fact, as n gets larger, more and more numbers just above n^2 are also in the sequence. For a particular n, the integers between n^2 and (n + 1/10)^2 are in this sequence. - Alonso del Arte, Mar 16 2019
LINKS
Nathaniel Johnston, Table of n, a(n) for n = 1..10000
FORMULA
A023961(a(n)) = 0. - Michel Marcus, Sep 21 2015
a(n) = 10n + O(sqrt(n)). - Charles R Greathouse IV, Sep 08 2022
EXAMPLE
sqrt(145) = 12.041594578792295..., so 145 is in the sequence.
sqrt(146) = 12.083045973594572..., so 146 is also in the sequence.
sqrt(147) = 12.124355652982141..., so 147 is not in the sequence.
MAPLE
A034096 := proc(n) option remember: local k, rt: if(n=1)then return 26: else k:=procname(n-1)+1: do rt:=sqrt(k): if(not frac(rt)=0 and floor(10*rt) mod 10 = 0)then return k: fi: k:=k+1: od: fi: end: seq(A034096(n), n=1..50); # Nathaniel Johnston, May 04 2011
seq(seq(x, x=floor(n^2) +1 .. ceil((n+1/10)^2)-1), n=1..100); # Robert Israel, Sep 21 2015
MATHEMATICA
zdQ[n_] := Module[{c = Sqrt[n], sr, i, l}, sr = RealDigits[c, 10, 5]; i = Last[sr] + 1; l = First[sr]; l[[i]] == 0 && !IntegerQ[c]]; Select[Range[700], zdQ] (* Harvey P. Dale, Oct 10 2011 *)
Flatten[Table[Range[n^2 + 1, Floor[(n + 1/10)^2]], {n, 25}]] (* Alonso del Arte, Mar 16 2019 *)
PROG
(PARI) isok(n) = !issquare(n) && !(floor(10*sqrt(n)) % 10); \\ Michel Marcus, Sep 21 2015
(PARI) is(n)=my(s=sqrtint(n), s2=s^2); s2+s\5 >= n && s2 < n \\ Charles R Greathouse IV, Sep 07 2022
(PARI) list(lim)=my(v=List(), s=sqrtint(lim\=1)); for(n=5, s-1, for(i=n^2+1, n^2+n\5, listput(v, i))); for(i=s^2+1, min(s^2+s\5, lim), listput(v, i)); Vec(v) \\ Charles R Greathouse IV, Sep 08 2022
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
Patrick De Geest, Sep 15 1998
EXTENSIONS
Name clarified by Michel Marcus, Sep 21 2015
STATUS
approved