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Search: id:A110557
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| 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; listen)
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OFFSET
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1,2
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COMMENT
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First differences are sqrt(2)'s shadow. Never twice the same integer in sequence or first differences.
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EXAMPLE
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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...
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MATHEMATICA
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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 *)
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CROSSREFS
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Cf. A002193.
Sequence in context: A098685 A006096 A099915 this_sequence A016304 A016849 A016297
Adjacent sequences: A110554 A110555 A110556 this_sequence A110558 A110559 A110560
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KEYWORD
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easy,nonn,base
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AUTHOR
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Eric Angelini & Alexandre Wajnberg (eric.angelini(AT)kntv.be), Sep 14 2005
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(at)rgwv.com), Oct 10 2005
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