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

3,2

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

Formula

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

Mathematica

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

Prog

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

Crossrefs

Cf. A061039.

Sequence in context: A156722 A152565 A174497 * A011376 A011452 A199952

Adjacent sequences: A146319 A146320 A146321 * A146323 A146324 A146325

Keyword

nonn,less

Author

Paul Curtz, Oct 30 2008

Status

approved