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A143992
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Numbers n such that the sum of the prime factors of n (counted with multiplicity) is a proper substring of n.
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0
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18, 144, 150, 168, 175, 198, 220, 230, 242, 246, 255, 322, 366, 444, 624, 1166, 1243, 1323, 1330, 1331, 1462, 1480, 1530, 1992, 2187, 2230, 2240, 2406, 2436, 2625, 2650, 2673, 2730, 2744, 2808, 2925, 3024, 3125, 3182, 3264, 3286, 3366, 3388, 3420, 3484
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| "Proper" is needed in the definition to exclude 4 and all primes.
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EXAMPLE
| a(3)=144=2*2*2*2*3*3 and 2+2+2+2+3+3=14 and 14 is a substring of 144.
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MATHEMATICA
| pfQ[n_]:=Module[{x=Total[Times@@@FactorInteger[n]], idx}, idx=IntegerDigits[x]; MemberQ[Partition[IntegerDigits[n], Length[idx], 1], idx]&&x!=n]
Select[Range[0, 3500], pfQ] (* From Harvey P. Dale, Feb 09 2011 *)
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CROSSREFS
| Sequence in context: A081074 A125355 A126513 * A127408 A008452 A126900
Adjacent sequences: A143989 A143990 A143991 * A143993 A143994 A143995
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KEYWORD
| base,nonn
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AUTHOR
| Gil Broussard (gilbroussard(AT)bellsouth.net), Sep 07 2008
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EXTENSIONS
| Corrected by Harvey P. Dale, Feb 09 2011
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