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A115927
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a(n) is the number of k such that k and n*k, taken together, are pandigital.
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11
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0, 48, 6, 8, 12, 0, 1, 16, 3, 0, 0, 1, 1, 6, 3, 1, 19, 6, 4, 12, 0, 3, 3, 4, 3, 9, 2, 1, 8, 2, 0, 16, 1, 3, 14, 0, 3, 7, 3, 4, 0, 3, 1, 13, 4, 1, 6, 0, 1, 12, 0, 2, 28, 1, 4, 6, 1, 3, 6, 3, 0, 28, 1, 1, 10, 1, 1, 4, 5, 7, 0, 3, 3, 11, 0, 2, 8, 1, 1, 46, 0, 0, 5, 3, 1, 7, 5, 6, 8, 3, 0, 13, 2, 3
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OFFSET
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1,2
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COMMENTS
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There are 1549586 nonzero terms in a(n). The largest n for which a(n) > 0 is 987654320. The largest a(n) is a(2) = 48. - Chai Wah Wu, May 24 2015
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LINKS
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EXAMPLE
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a(7)=1 since there is only one number, k=14076, such that k and 7*k=98532.
a(9)=3 since there are 3 such numbers: 10638, 10647 and 10836.
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PROG
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(Python)
from itertools import permutations
l = {}
for d in permutations('0123456789', 10):
....if d[0] != '0':
........for i in range(9):
............if d[i+1] != '0':
................q, r = divmod(int(''.join(d[:i+1])), int(''.join(d[i+1:])))
................if not r:
....................if q in l:
........................l[q] += 1
....................else:
........................l[q] = 1
for d in l:
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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