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A050689 Sum of digits of composite a(n) equals number of its prime factors, with multiplicity. 1
12, 30, 32, 40, 102, 220, 240, 500, 600, 1002, 1012, 1104, 1152, 1210, 1320, 1500, 2001, 2002, 2020, 2040, 2120, 2240, 2300, 3010, 3040, 3300, 4032, 4100, 4320, 5100, 5200, 6400, 7000, 7200, 10001, 10002, 10011, 10030, 10040, 10080, 10140, 10220 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..42.

EXAMPLE

E.g. 2002 = 2+0+0+2 = 4 prime factors namely 2.7.11.13.

MATHEMATICA

Select[Range[10300], !PrimeQ[#]&&PrimeOmega[#]==Total[IntegerDigits[#]]&] (* Jayanta Basu, May 30 2013 *)

CROSSREFS

Cf. A050690.

Sequence in context: A049725 A183723 A247152 * A144565 A115912 A083096

Adjacent sequences:  A050686 A050687 A050688 * A050690 A050691 A050692

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Aug 15 1999.

STATUS

approved

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Last modified December 9 04:41 EST 2016. Contains 278960 sequences.