A106586 Digit next to last in squares ending in 6.

1, 3, 9, 5, 7, 7, 5, 9, 3, 1, 1, 3, 9, 5, 7, 7, 5, 9, 3, 1, 1, 3, 9, 5, 7, 7, 5, 9, 3, 1, 1, 3, 9, 5, 7, 7, 5, 9, 3, 1, 1, 3, 9, 5, 7, 7, 5, 9, 3, 1, 1, 3, 9, 5, 7, 7, 5, 9, 3, 1, 1, 3, 9, 5, 7, 7, 5, 9, 3, 1, 1, 3, 9, 5, 7, 7, 5, 9, 3, 1, 1, 3, 9, 5, 7, 7, 5, 9, 3, 1, 1, 3, 9, 5, 7, 7, 5, 9, 3, 1, 1, 3, 9, 5, 7

Offset

1,2

Comments

Entries are always one of the odd digits 1,3,5,7,9.

Palindrome of period 10. [From Paul Curtz, Jan 04 2009]

Links

Table of n, a(n) for n=1..105.

Index entries for linear recurrences with constant coefficients, signature (1,-1,1,-1,1,-1,1,-1,1).

Formula

G.f. -x*(1 +2*x +7*x^2 -2*x^3 +9*x^4 -2*x^5 +7*x^6 +2*x^7 +x^8) / ( (x-1) *(1+x+x^2+x^3+x^4) *(1-x+x^2-x^3+x^4) ). - R. J. Mathar, Jul 28 2013

Mathematica

Mod[Floor[ #^2/10], 10] & /@ Select[Range[700], Mod[ #^2, 10] == 6 &] (* Ray Chandler, May 13 2005  *)

Crossrefs

Cf. A000290.

Sequence in context: A320960 A193075 A285264 * A010633 A332564 A199053

Adjacent sequences: A106583 A106584 A106585 * A106587 A106588 A106589

Keyword

nonn,base

Author

Lekraj Beedassy, May 10 2005

Extensions

Extended by Ray Chandler, May 13 2005

Status

approved