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A152987
Sum of proper divisors minus the number of proper divisors of the number of partitions of n, A000041(n).
1
0, 0, 0, 0, 0, 0, 6, 11, 35, 47, 57, 16, 0, 98, 187, 146, 176, 184, 525, 326, 1525, 1007, 254, 1632, 1275, 4261, 3311, 2859, 1476, 7489, 4383, 4408, 7624, 9859, 7450, 0, 5428, 9086, 38472, 50191, 29898, 33867, 41264, 22030, 47947, 109323, 107783, 77168
OFFSET
1,7
COMMENTS
Note that if a(n) != 0 then the number of partitions of n (A000041(n)) is a composite number (A002808), otherwise A000041(n) is a noncomposite number (A008578). See A152770.
FORMULA
a(n) = A001065(A000041(n)) - A032741(A000041(n)) = A152770(A000041(n)).
MAPLE
A000041 := proc(n) combinat[numbpart](n) ; end: A001065 := proc(n) numtheory[sigma](n)-n ; end: A032741 := proc(n) if n = 0 then 0; else numtheory[tau](n)-1 ; fi; end: A152987 := proc(n) local np ; np := A000041(n) ; A001065(np)-A032741(np) ; end: for n from 1 to 80 do printf("%d, ", A152987(n)) ; end: # R. J. Mathar, Jan 22 2009
KEYWORD
easy,nonn
AUTHOR
Omar E. Pol, Dec 21 2008
EXTENSIONS
More terms from R. J. Mathar, Jan 22 2009
STATUS
approved