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A121342
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Composite numbers that are concatenations of their distinct prime divisors.
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0
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735, 3792, 1341275, 13115375, 22940075, 29373375, 71624133, 311997175, 319953792, 1019127375, 1147983375, 1734009275, 7350032375
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Larger terms of this sequence were calculated by Giovanni Resta (g.resta AT iit.cnr.it) and Farideh Firoozbakht (mymontain AT yahoo.com). This sequence is a subsequence of A083360 (Subsequence of sequence A083359 in which factors do not overlap in the number), which is a subsequence of A083359 (Visible Factor Numbers, or VPNs: numbers n with the property that every prime factor of n can be found in the decimal expansion of n and every digit of n can be found in a prime factor. No additional 0's and 1's are allowed). Also, this sequence is a subsequence of A096595 (Numbers n with the property that n is an anagram of the digits of the distinct prime factors of n).
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EXAMPLE
| For example: 735 = 3*5*7^2 and 3792 = 2^4*3*79.
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MATHEMATICA
| fQ[n_] := !PrimeQ@n && MemberQ[ FromDigits /@ (Flatten@# & /@ IntegerDigits[ Permutations[ First /@ FactorInteger@n]]), n]; Do[ If[fQ@n, Print@n], {n, 10^7/4}] (* Robert G. Wilson v Sep 02 2006 *)
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CROSSREFS
| Cf. A083359, A083360, A083361, A096595.
Sequence in context: A096595 A083359 A083360 * A067866 A157198 A156954
Adjacent sequences: A121339 A121340 A121341 * A121343 A121344 A121345
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KEYWORD
| base,nonn
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AUTHOR
| Tanya Khovanova (tanyakh(AT)yahoo.com), Aug 28 2006
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