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A001103
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Numbers n such that (n / product of digits of n) is 1 or a prime.
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2
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1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 15, 24, 36, 115, 175, 212, 624, 735, 816, 1115, 1184, 1197, 1416, 2144, 3171, 3276, 3915, 6624, 7119, 8832, 9612, 11133, 11212, 11331, 12128, 12216, 12768, 13131, 21184, 21728, 24912, 31113, 31488, 32172, 32616, 35175
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Klaus Brockhaus, Table of n, a(n) for n = 1..448 (terms < 10^8)
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MATHEMATICA
| okQ[n_] := Block[{p = Times @@ IntegerDigits[n]}, n == p || PrimeQ[n/p]]; Select[ Range[36000], okQ]
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PROG
| (MAGMA) IsA001103:=func< n | p ne 0 and n mod p eq 0 and (q eq 1 or IsPrime(q)) where q is (p eq 0 select 0 else n div p) where p is &*Intseq(n) >; [ n: n in [1..40000] | IsA001103(n) ]; - Klaus Brockhaus, Jan 24 2011
(Haskell)
a001103 n = a001103_list !! (n-1)
a001103_list = filter f a052382_list where
f x = m == 0 && (x' == 1 || a010051 x' == 1) where
(x', m) = divMod x $ a007954 x
-- Reinhard Zumkeller, Nov 02 2011
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CROSSREFS
| Cf. A007954, A066577.
Cf. A052382, A010051, A007602, A188642.
Sequence in context: A030721 A190296 A143288 * A084034 A147591 A033074
Adjacent sequences: A001100 A001101 A001102 * A001104 A001105 A001106
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KEYWORD
| nonn,base,easy,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Bill Moran (moran1(AT)llnl.gov)
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