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A110069
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Numbers n such that n=(d_1+d_2+...+d_k)*prime(d_1*d_2*...*d_k) where d_1 d_2 ... d_k is the decimal expansion of n.
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0
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OFFSET
| 1,1
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COMMENTS
| There is no further term up to 660000000.
This sequence is finite since (d_1+d_2+...+d_k)*prime(d_1*d_2*...*d_k) <= 9k * prime(9^k) << 9^k * k^2 << n. The bound can be made effective using the results of Dusart or others; for example, a(n) < 10^150. These can be improved with more work, but completing the sequence seems hard. [Charles R Greathouse IV, May 07, 2011]
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EXAMPLE
| 236256594 is in the sequence because 236256594=(2+3+6+2+5+6+5+9+4)*prime(2*3*6*2*5*6*5*9*4).
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MATHEMATICA
| Do[h = IntegerDigits[m]; l = Length[h]; If[Min[h] > 0 && m == Sum[h[[k]], {k, l}]*(Prime[Product[h[[k]], {k, l}]]), Print[m]], {m, 655000000}]
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CROSSREFS
| Cf. A097640.
Sequence in context: A046507 A151422 A186137 * A006028 A206018 A186584
Adjacent sequences: A110066 A110067 A110068 * A110070 A110071 A110072
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KEYWORD
| more,nonn,base,fini
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AUTHOR
| Farideh Firoozbakht (mymontain(AT)yahoo.com), Jul 17 2005
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