A175081 -id:A175081 - cp's OEIS frontend

A175082 Possible values for sum of perfect divisors of n.

1, 2, 3, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 26, 28, 29, 30, 31, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75

Offset: 1

Jaroslav Krizek, Jan 24 2010

nonn

Perfect divisor of n is divisor d such that d^k = n for some k >= 1. See A175067 (sum of perfect divisors of n) and A175081 (values taken by the sum of perfect divisors of n (A175067) sorted into ascending order).

Complement of A001597(n+1) for n >= 1 (perfect powers >= 4). a(n) = A007916(n-1) for n >= 2. [From Jaroslav Krizek, Jan 30 2010]

A175083 Number of numbers whose sum of perfect divisors is equal to n.

Original entry on oeis.org

1, 1, 1, 0, 1, 2, 1, 0, 0, 2, 1, 2, 1, 1, 1, 0, 1, 1, 1, 1, 1, 2, 1, 1, 0, 1, 0, 1, 1, 3, 1, 0, 1, 2, 1, 0, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1

Offset: 1

Jaroslav Krizek, Jan 24 2010

nonn

Perfect divisor of m is divisor d such that d^k = m for some k >= 1. See A175067 (sum of perfect divisors of n) and A175081 (values taken by the sum of perfect divisors of n (A175067) sorted into ascending order).

Antti Karttunen, Table of n, a(n) for n = 1..65537

Cf. A175067, A175081.

up_to = 65537;
A175067(n) = (n+if(!ispower(n),0,sumdiv(n,d,if((d>1)&&(dA175083list(up_to) = { my(range = Map(), v = vector(up_to), x); for(n=1,up_to,x=A175067(n); mapput(range,x,1+if(!mapisdefined(range,x), 0, mapget(range,x)))); for(n=1,up_to,v[n]=if(!mapisdefined(range,n), 0, mapget(range,n))); (v); };
v175083 = A175083list(up_to);
A175083(n) = v175083[n]; \\ Antti Karttunen, Sep 25 2018

More terms from Antti Karttunen, Sep 25 2018

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A175082 Possible values for sum of perfect divisors of n.

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A175083 Number of numbers whose sum of perfect divisors is equal to n.

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