A396618 a(n) is the number of n-digit terms in A192689 with a(1) = 4.

4, 3, 4, 8, 26, 70, 206, 674, 2032, 6431, 20096, 63708, 200646, 634782, 2005025, 6341137, 20044802, 63389326, 200432444, 633827657, 2004269529

Offset

1,1

Links

Table of n, a(n) for n=1..21.

Mathematica

A192689Q[k_]:=NoneTrue[Table[Mod[k, 10^d], {d, IntegerLength[k] - 1}], IntegerQ[Sqrt[#]] &]; a[n_]:=KroneckerDelta[n, 1]+Length[Select[Range[Ceiling[Sqrt[10^(n - 1)]], Floor[Sqrt[10^n-1]]]^2, A192689Q]]; Array[a, 12]

Crossrefs

Cf. A017934, A017936, A192689.

Sequence in context: A257840 A388148 A132984 * A277528 A358736 A340768

Adjacent sequences: A396615 A396616 A396617 * A396619 A396620 A396621

Keyword

nonn,base,more

Author

Stefano Spezia, May 31 2026

Extensions

a(18)-a(21) from Michael S. Branicky, Jun 10 2026

Status

approved