A125309 Numbers n such that twice the sum of the prime factors of n equals the product of the digits of n.

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

Offset: 1

Author

Tanya Khovanova, Dec 10 2006

Keywords

• base
• nonn

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

Examples

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

Crossrefs

Similar to A067173 = numbers n such that the sum of the prime factors of n equals the product of the digits of n.

Programs

Mathematica

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

Extensions

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