

A334023


Sum of unitary divisors of n that are larger than sqrt(n).


3



0, 2, 3, 4, 5, 9, 7, 8, 9, 15, 11, 16, 13, 21, 20, 16, 17, 27, 19, 25, 28, 33, 23, 32, 25, 39, 27, 35, 29, 61, 31, 32, 44, 51, 42, 45, 37, 57, 52, 48, 41, 84, 43, 55, 54, 69, 47, 64, 49, 75, 68, 65, 53, 81, 66, 64, 76, 87, 59, 107, 61, 93, 72, 64, 78, 132, 67
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OFFSET

1,2


LINKS



FORMULA



EXAMPLE

The unitary divisors of 12 are {1, 3, 4, 12}, 4 and 12 are larger than sqrt(12) and their sum is 4 + 12 = 16, hence a(12) = 16.


MATHEMATICA

a[n_] := DivisorSum[n, # &, #^2 > n && CoprimeQ[#, n/#] &]; Array[a, 100]


PROG

(PARI) a(n) = sumdiv(n, d, if(gcd(d, n/d)==1 && d>sqrt(n), d)); \\ Jinyuan Wang, Apr 12 2020


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



