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A087004
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Numbers whose number of divisors equals the sum of their separate prime-power decompositions.
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1
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60, 120, 180, 504, 720, 11550, 12180, 17940, 19380, 21252, 22230, 26334, 27846, 29172, 32340, 34440, 34580, 43470, 48840, 56430, 59220, 59670, 63240, 66120, 70686, 82824, 85140, 91350, 95700, 95940, 99528, 112840, 113220, 113652, 115368
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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REFERENCES
| S. Kahan,"Divisor Advisory", Journal of Recreational Mathematics 30(1) 41-4 1999-2000 Baywood NY.
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EXAMPLE
| 504=2^3*3^2*7 is in the sequence because d(504)=A000005(504)=(3+1)*(2+1)*(1+1)=24 = 2^3 + 3^2 + 7. Similarly for 32340=2^2*3*5*7^2*11, where d(32340) = 2^2 + 3 + 5 + 7^2 + 11 = 72.
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CROSSREFS
| Cf. A078511.
Sequence in context: A098136 A060793 A169823 * A177871 A049058 A056501
Adjacent sequences: A087001 A087002 A087003 * A087005 A087006 A087007
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KEYWORD
| nonn
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AUTHOR
| Lekraj Beedassy (blekraj(AT)yahoo.com), Oct 13 2003
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