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Search: id:A115645
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| A115645 |
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Powerful(1) numbers (A001694) that are sums of distinct factorials. |
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+0
3
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| 1, 8, 9, 25, 27, 32, 121, 128, 144, 729, 841, 864, 5041, 5184, 40328, 41067, 45369, 45387, 46208, 46225, 363609, 403225, 3674889, 43954688, 6230694987, 1401602635449
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OFFSET
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1,2
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COMMENT
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Factorials 0! and 1! are not considered distinct.
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EXAMPLE
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6230694987 = 13!+10!+8!+7!+4!+2!+1! = 3^3*11^2*1381^2.
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MATHEMATICA
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pwfQ[n_] := n==1 || Min[Last /@ FactorInteger@n] > 1; fac=Range[20]!; lst={}; Do[ n = Plus@@(fac*IntegerDigits[k, 2, 20]); If[pwfQ[n], AppendTo[lst, n]], {k, 2^20-1}]; lst
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CROSSREFS
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Cf. A001694, A025494, A115644, A115646, A089359.
Sequence in context: A032462 A077599 A109097 this_sequence A068435 A124438 A124184
Adjacent sequences: A115642 A115643 A115644 this_sequence A115646 A115647 A115648
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KEYWORD
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nonn
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AUTHOR
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Giovanni Resta (g.resta(AT)iit.cnr.it), Jan 27 2006
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