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A121342 Composite numbers that are a concatenation of their distinct prime divisors in some order. 0
735, 3792, 1341275, 13115375, 22940075, 29373375, 71624133, 311997175, 319953792, 1019127375, 1147983375, 1734009275, 7350032375, 17370159615 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Larger terms of this sequence were calculated by Giovanni Resta and Farideh Firoozbakht. 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).

LINKS

Table of n, a(n) for n=1..14.

EXAMPLE

For example: 735 = 3*5*7^2 and 3792 = 2^4*3*79.

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 *)

CROSSREFS

Cf. A083359, A083360, A083361, A096595.

Sequence in context: A096595 A083359 A083360 * A067866 A157198 A156954

Adjacent sequences:  A121339 A121340 A121341 * A121343 A121344 A121345

KEYWORD

base,nonn

AUTHOR

Tanya Khovanova, Aug 28 2006

EXTENSIONS

a(14) from Emmanuel Vantieghem, Nov 30 2016

STATUS

approved

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Last modified May 30 06:51 EDT 2017. Contains 287302 sequences.