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A348565
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Numbers with factorial base expansion (d(1), ..., d(k)) such that, for i = 1..k, either d(i) > 0 and d(d(i)) = i or d(i) = 0.
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0
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0, 1, 2, 5, 6, 10, 14, 19, 23, 24, 36, 46, 54, 74, 86, 97, 109, 119, 120, 138, 168, 186, 204, 220, 238, 264, 282, 366, 414, 466, 482, 500, 530, 548, 566, 601, 619, 649, 667, 685, 701, 719, 720, 792, 834, 960, 1032, 1074, 1128, 1212, 1284, 1324, 1396, 1438
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OFFSET
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1,3
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COMMENTS
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Leading zeros are ignored.
This sequence is a variant of A348056.
If m is a term, then so is A153880(m).
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LINKS
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EXAMPLE
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The first terms, alongside their factorial base expansion, are:
n a(n) fact(a(n))
-- ---- ----------
1 0 0
2 1 1
3 2 10
4 5 21
5 6 100
6 10 120
7 14 210
8 19 301
9 23 321
10 24 1000
11 36 1200
12 46 1320
13 54 2100
14 74 3010
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PROG
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(PARI) is(n) = { my (d=[]); for (r=2, oo, if (n==0, for (i=1, #d, if (d[i] && d[d[i]]!=i, return (0))); return (1), d=concat(n%r, d); n\=r)) }
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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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