login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A110557 Shadow of sqrt(2). 2
1, 15, 157, 170, 175, 181, 183, 186, 193, 223, 232, 282, 286, 294, 374, 390, 478, 550, 970, 1066, 2046, 2124, 2180, 3147, 3165, 3240, 3277, 3346, 3826, 3899, 3916, 3982, 4061, 4798, 5788, 6520, 6567, 6651, 6713, 6723, 6793, 6831, 7681, 8068, 8121, 8164 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
First differences are sqrt(2)'s shadow. Never twice the same integer in sequence or first differences.
LINKS
EXAMPLE
The first line below is the sequence, the second gives the first differences:
1..15...157..170.175.181.183.186.193..223.232..282.286.294
.14..142...13...5...6...2...3...7...30...9...50...4...8 <- sqrt(2) shadow
sqrt(2) = 1.4142135623730950488016887242096980785696718753769...
MATHEMATICA
a[1] = 1; a[n_] := a[n] = Block[{c = RealDigits[ Sqrt[2], 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, 46}] (* Robert G. Wilson v, Oct 10 2005 *)
CROSSREFS
Cf. A002193.
Sequence in context: A346843 A341918 A099915 * A016304 A016849 A300077
KEYWORD
easy,nonn,base
AUTHOR
EXTENSIONS
More terms from Robert G. Wilson v, Oct 10 2005
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 23 20:31 EST 2024. Contains 370288 sequences. (Running on oeis4.)