Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A110621
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A110621 Shadow of Pi. +0
1
1, 4, 18, 33, 42, 44, 50, 55, 90, 98, 195, 288, 311, 395, 457, 521, 859, 891, 898, 1848, 1876, 2717, 3688, 3757, 3796, 4733, 5243, 5301, 5321, 6295, 6389, 6434, 6526, 6556, 6634, 6650, 6690, 7318, 7938, 8027, 9013, 9293, 9327, 9409, 9462, 9883, 10053 (list; graph; listen)
OFFSET

1,2

COMMENT

First differences are Pi's shadow. Never twice the same integer in sequence or first differences.

EXAMPLE

The first line hereunder is the sequence, the second line are the first differences:

1.4..18..33.42.44.50.55..90.98..195..288..311...

.3.14..15..9..2..6..5..35..8..97...93...23 <-- Pi shadow

(Pi=3.141592653589793238462643383279502884197169399...)

MATHEMATICA

a[1] = 1; a[n_] := a[n] = Block[{c = RealDigits[Pi, 10, 300][[1]], k = 1, t = Table[a[i], {i, n - 1}]}, d = Drop[t, 1] - Drop[t, -1]; b = Drop[c, Length[ Flatten[ IntegerDigits /@ d]]]; e = Union[ Join[t, d]]; While[f = FromDigits[ Take[b, k]]; Position[e, f] != {} || b[[k + 1]] == 0, k++ ]; f + a[n - 1]]; Table[ a[n], {n, 47}] (* Robert G. Wilson v *)

CROSSREFS

Cf. A000796.

Sequence in context: A095823 A092116 A083969 this_sequence A124978 A031081 A009956

Adjacent sequences: A110618 A110619 A110620 this_sequence A110622 A110623 A110624

KEYWORD

easy,nonn,base

AUTHOR

Eric Angelini & Alexandre Wajnberg (eric.angelini(AT)kntv.be), Sep 14 2005

EXTENSIONS

More terms from Robert G. Wilson v (rgwv(at)rgwv.com), Oct 10 2005

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified December 19 12:50 EST 2009. Contains 171053 sequences.


AT&T Labs Research