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A126430
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a(n)-a(n-1) is the smallest integer missing in the auxiliary set composed of the previous terms and sums and differences of previous pairs of the sequence.
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5
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1, 3, 8, 14, 24, 36, 54, 73, 93, 119, 148, 179, 213, 254, 296, 339, 384, 431, 479, 531, 587, 645, 706, 769, 833, 899, 966, 1037, 1114, 1194, 1276, 1360, 1449, 1540, 1638, 1737, 1839, 1942, 2046, 2156, 2269, 2384, 2505, 2628, 2756, 2887, 3019, 3155, 3292, 3431
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OFFSET
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1,2
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LINKS
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EXAMPLE
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a(3)-a(2) = 5 because 1=a(1), 2=(a(2)-a(1), 3=a(2), 4=a(1)+a(2)= maximum of the auxiliary set
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PROG
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(Python)
keep = [1, 3]
for aa in range(999):
....flag = False
....temp = set()
....for x in keep:
........for y in keep:
............if x != y:
................temp.add(x+y)
................temp.add(abs(x-y))
............temp.add(x)
............temp.add(y)
....now = sorted(list(temp))
....for x in range(1, len(now)):
........if now[x] - now[x-1] != 1:
............keep.append(keep[-1]+now[x-1]+1)
............flag = True
............break
....if not flag:
........keep.append(keep[-1]+max(now)+1)
with open("A126430b.txt", "w") as g:
....for x, y in enumerate(keep):
........g.write(str(x+1)+" "+str(y)+"\n")
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Philippe LALLOUET (philip.lallouet(AT)wanadoo.fr), Mar 11 2007
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EXTENSIONS
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STATUS
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approved
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