

A125309


Numbers n such that twice the sum of the prime factors of n equals the product of the digits of n.


0



4, 25, 76, 125, 187, 255, 437, 629, 1152, 1276, 1298, 1352, 1617, 1668, 2337, 3363, 3618, 4116, 4439, 5891, 6432, 8279, 11178, 13125, 14144, 14812, 14824, 18647, 22165, 22466, 23472, 24727, 24743, 25631, 26128, 32978, 37329, 42983, 48442
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OFFSET

1,1


COMMENTS

Number of terms less than 10^n: 1, 3, 8, 22, 48, 103, 230, 611, ...; number of odd terms less than 10^n: 0, 1, 6, 12, 21, 51, 120, 331, ..., .  Robert G. Wilson v, Dec 12 2006


LINKS

Table of n, a(n) for n=1..39.


EXAMPLE

Prime factors of 76 are 2 and 19; twice their sum is 42 which the product of 7 and 6  the digits of 76.


MATHEMATICA

Select[Range[2, 20000], Times @@ IntegerDigits[ # ] == 2 Plus @@ Transpose[FactorInteger[ # ]][[1]] &]


CROSSREFS

Similar to A067173 = numbers n such that the sum of the prime factors of n equals the product of the digits of n.
Sequence in context: A077205 A180569 A302821 * A273361 A266126 A303514
Adjacent sequences: A125306 A125307 A125308 * A125310 A125311 A125312


KEYWORD

base,nonn


AUTHOR

Tanya Khovanova, Dec 10 2006


EXTENSIONS

More terms from Robert G. Wilson v, Dec 12 2006


STATUS

approved



