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

Author

Gil Broussard, May 12 2010

Keywords

• nonn
• base

Comments

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

Examples

			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"
		

Links

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

Crossrefs

Cf. A000290.

Programs

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 *)