A177715 The position within sqrt(n) at which n first occurs.

0, 4, 2, 0, 36, 38, 4, 1, 0, 88, 19, 51, 221, 318, 48, 0, 11, 98, 24, 143, 60, 40, 8, 108, 0, 144, 9, 267, 32, 188, 183, 154, 370, 44, 107, 0, 117, 25, 10, 148, 145, 107, 4, 234, 48, 298, 252, 31, 0, 102, 211, 119, 178, 352, 118, 224, 63, 9, 107, 103, 239, 130, 94, 0, 16

Offset

1,2

Comments

Determine position from the decimal point, and define a(n)=0 for perfect squares (A000290).

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

a(1)=0 because 1 is a perfect square.
a(2)=4 because the first "2" occurs at position 4 in "1.41421356...".
a(5)=36 because the first "5" occurs at position 36 in "2.236067977499789696409173668731276235"

Mathematica

max = 500; a[n_] := If[IntegerQ @ Sqrt[n], 0, SequencePosition[(r = RealDigits[ FractionalPart @ Sqrt[n], 10, max])[[1]], IntegerDigits[n]][[1, 1]] - r[[2]]]; Array[a, 100] (* Amiram Eldar, Sep 25 2020 *)

Crossrefs

Cf. A000290.

Sequence in context: A019155 A107724 A247092 * A164789 A203986 A204690

Adjacent sequences: A177712 A177713 A177714 * A177716 A177717 A177718

Keyword

nonn,base

Author

Gil Broussard, May 12 2010

Status

approved