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A159555
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Numbers m where m^2 divides A159553(m), where A159553(m) = Sum_{k=0..m} binomial(m,k) * gcd(m,k).
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0
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1, 6, 22, 72, 114, 148, 164, 260, 261, 780, 1078, 1184, 1266, 2952, 4674, 21868
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OFFSET
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1,2
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COMMENTS
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For the purpose of this sequence, gcd(m,0) = m.
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LINKS
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MAPLE
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A159068 := proc(n) option remember; add(binomial(n, k)*gcd(k, n), k=1..n) ; end: A159553 := proc(n) option remember ; A159068(n)+n; end: isA159555 := proc(n) if A159553(n) mod ( n^2) = 0 then true; else false; fi; end: for n from 1 do if isA159555(n) then printf("%d, \n", n) ; fi; od: # R. J. Mathar, Apr 29 2009
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PROG
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(PARI) f(n) = sum(k=0, n, binomial(n, k) * gcd(n, k)); \\ A159553
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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