A146322 a(n) = A061039(n) mod 9.

0, 7, 7, 1, 4, 1, 8, 1, 4, 5, 7, 7, 8, 4, 1, 8, 1, 4, 7, 7, 7, 7, 4, 1, 8, 1, 4, 2, 7, 7, 4, 4, 1, 8, 1, 4, 2, 7, 7, 2, 4, 1, 8, 1, 4, 4, 7, 7, 5, 4, 1, 8, 1, 4, 4, 7, 7, 7, 4, 1, 8, 1, 4, 8, 7, 7, 5, 4, 1, 8, 1, 4, 1, 7, 7, 3, 4, 1, 8, 1, 4, 6, 7, 7, 1, 4, 1, 8, 1, 4, 5, 7, 7, 8, 4, 1, 8, 1, 4, 7, 7, 7, 1, 4, 1, 8, 1, 4, 8, 7, 7, 4, 4, 1, 8, 1, 4, 2, 7, 7

Offset: 3

Author

Paul Curtz, Oct 30 2008

Keywords

• nonn
• less

Comments

Is the number 0.77141814577... rational? Note groups of 4,1,8 at positions 7, 16, 25, 34, 43 etc.; also 7,7 positions 4, 13, 21, 31, 40, 49 etc.

From Paschen spectrum of hydrogen.

The number 6 appears at positions n=84, 159, 327, 402 etc.; the number 3 at n=78, 165, 321 etc; the number 0 at n=3, 240, 246 etc. - R. J. Mathar, Feb 28 2009

Starting with a(7) the pattern {4, 1, 8, 1, 4, b(n), 7, 7, c(n)} is repeated with b(n) and c(n) containing numbers zero to nine. - G. C. Greubel, Mar 08 2022

Links

• G. C. Greubel, Table of n, a(n) for n = 3..5000

Crossrefs

Cf. A061039.

Programs

Mathematica

Mod[Numerator[1/9 - 1/(Range[3, 150])^2], 9] (* G. C. Greubel, Mar 08 2022 *)

Sage

[numerator(1/9 - 1/n^2)%9 for n in (3..150)] # G. C. Greubel, Mar 08 2022

Formula

a(n) = A061039(n) mod 9.