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A035333
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Concatenation of two or more consecutive positive integers.
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12
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12, 23, 34, 45, 56, 67, 78, 89, 123, 234, 345, 456, 567, 678, 789, 910, 1011, 1112, 1213, 1234, 1314, 1415, 1516, 1617, 1718, 1819, 1920, 2021, 2122, 2223, 2324, 2345, 2425, 2526, 2627, 2728, 2829, 2930, 3031, 3132, 3233, 3334, 3435, 3456, 3536, 3637, 3738
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listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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PROG
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(Python)
import heapq
from itertools import islice
def agen():
c = 12
h = [(c, 1, 2)]
nextcount = 3
while True:
(v, s, l) = heapq.heappop(h)
yield v
if v >= c:
c = int(str(c) + str(nextcount))
heapq.heappush(h, (c, 1, nextcount))
nextcount += 1
l += 1; v = int(str(v)[len(str(s)):] + str(l)); s += 1
heapq.heappush(h, (v, s, l))
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CROSSREFS
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See also A007908 for concatenation of 1 through n.
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KEYWORD
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easy,nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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