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Search: id:A108912
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| A108912 |
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Shadow of constant "e". |
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+0
1
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| 1, 3, 10, 28, 309, 317, 601, 606, 696, 700, 752, 787, 1147, 1434, 1481, 1494, 2020, 2026, 2050, 2059, 2136, 2193, 4663, 4756, 4825, 4924, 4983, 5557, 5653, 12620, 12682, 13454, 13494, 13570, 14200, 14553, 14607, 14682, 14776, 15347, 15385
(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 constant e's shadow. Never twice the same integer in sequence or first differences.
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EXAMPLE
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The first line hereunder is the sequence, the second line gives the first differences:
1.3.10..28...309.317...601.606..696.700..752..787...1147...1434..1481...
.2.7..18..281...8...284...5...90...4...52...35...360....287....47 <-- "e" shadow
e = 2.71828182845904523536028747135266249775724709369995...
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MATHEMATICA
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a[1] = 1; a[n_] := a[n] = Block[{c = RealDigits[E, 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, 41}] (* Robert G. Wilson v *)
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CROSSREFS
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Cf. A001113.
Sequence in context: A128135 A027252 A104574 this_sequence A055336 A084380 A092325
Adjacent sequences: A108909 A108910 A108911 this_sequence A108913 A108914 A108915
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KEYWORD
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base,easy,nonn,uned
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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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Corrected and extended by Robert G. Wilson v (rgwv(at)rgwv.com), Oct 10 2005
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