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Search: id:A081401
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| 1, 3, 5, 8, 11, 15, 18, 22, 26, 31, 35, 41, 46, 51, 55, 62, 67, 75, 80, 86, 92, 101, 106, 112, 119, 125, 131, 141, 147, 158, 163, 170, 178, 185, 191, 203, 212, 220, 226, 239, 246, 260, 267, 274, 284, 299, 305, 313, 320, 329, 337, 353, 360, 368, 375, 385, 396, 413
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OFFSET
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2,2
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FORMULA
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a(n)=Sum[k*e(k)] where k runs through indices of prime factors of n!, while e(k) is the exponent of corresponding prime factor.
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EXAMPLE
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n=8: 8!=40320=2.2.2.2.2.2.2.3.3.5.7, p-indices={1,2,3,4}, exponents={7,2,1,1}; a(8)=1.7+2.2+3.1+4.1=7+4+3+4=18.
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CROSSREFS
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Cf. A056239, A000142.
Sequence in context: A062009 A062484 A022433 this_sequence A003311 A108279 A002821
Adjacent sequences: A081398 A081399 A081400 this_sequence A081402 A081403 A081404
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Mar 31 2003
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