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A071791 Decimal expansion of the third (of 10) decimal selvage numbers; the n-th digit of a decimal selvage number, x, is equal to the tenths digit of n*x. 9
2, 5, 7, 0, 2, 5, 7, 0, 3, 5, 8, 0, 3, 5, 8, 1, 3, 6, 8, 1, 3, 6, 9, 1, 4, 6, 9, 1, 4, 7, 9, 2, 4, 7, 9, 2, 5, 7, 0, 2, 5, 7, 0, 3, 5, 8, 0, 3, 5, 8, 1, 3, 6, 8, 1, 3, 6, 9, 1, 4, 6, 9, 1, 4, 7, 9, 2, 4, 7, 9, 2, 5, 7, 0, 2, 5, 7, 0, 3, 5, 8, 0, 3, 5, 8, 1, 3, 6, 8, 1, 3, 6, 9, 1, 4, 6, 9, 1, 4, 7 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

In other words, this constant satisfies x = Sum_{n>=0} ( floor(10*n*x) (mod 10) ) / 10^n.

LINKS

Table of n, a(n) for n=0..99.

FORMULA

a(n) = floor(10*n*x) (mod 10), where x = Sum_{k>0} a(k)/10^k.

a(n) = 9 - A071875(n).

EXAMPLE

x = .25702570358035813681369146914792479257025703580358...

a(6) = 5 since floor(10*6*x) (mod 10) = 5.

The multiples of this constant x begin:

1*x = 0.2570257035803581368136914691479247925703...

2*x = 0.5140514071607162736273829382958495851405...

3*x = 0.7710771107410744104410744074437743777108...

4*x = 1.028102814321432547254765876591699170281...

5*x = 1.285128517901790684068457345739623962851...

6*x = 1.542154221482148820882148814887548755422...

7*x = 1.799179925062506957695840284035473547992...

8*x = 2.056205628642865094509531753183398340562...

9*x = 2.313231332223223231323223222331323133132...

10*x = 2.570257035803581368136914691479247925703...

11*x = 2.827282739383939504950606160627172718273...

12*x = 3.084308442964297641764297629775097510843...

wherein the tenths place of n*x yields the n-th digit of x.

MATHEMATICA

Clear[a]; a[1] = 2; a[2] = 5; a[n0 = 3] = 7; a[_] = 0; digits = 10^(n0-1); Do[a[n] = Mod[Floor[10*n*Sum[a[k]/10^k, {k, 1, n}]], 10], {n, n0+1, digits}]; Table[a[n], {n, 1, digits}]

PROG

Cf. A071789, A071790, A071792, A071793, A071873, A071874, A071875, A071876, A071877.

CROSSREFS

Sequence in context: A009376 A231364 A025123 * A248752 A021393 A181583

Adjacent sequences:  A071788 A071789 A071790 * A071792 A071793 A071794

KEYWORD

nonn,cons,base,nice

AUTHOR

Paul D. Hanna, Jun 06 2002

STATUS

approved

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Last modified November 20 10:41 EST 2017. Contains 294963 sequences.