A162195 -id:A162195 - cp's OEIS frontend

A162194 Sum of divisors of nonprime number A018252(n).

1, 7, 12, 15, 13, 18, 28, 24, 24, 31, 39, 42, 32, 36, 60, 31, 42, 40, 56, 72, 63, 48, 54, 48, 91, 60, 56, 90, 96, 84, 78, 72, 124, 57, 93, 72, 98, 120, 72, 120, 80, 90, 168, 96, 104, 127, 84, 144, 126, 96, 144, 195, 114, 124, 140, 96, 168, 186, 121, 126, 224, 108, 132

Offset: 1

Omar E. Pol, Jul 04 2009

Also, 1 together with the numbers A073255.

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Cf. A000203, A018252, A073255, A162194, A162195.

with(NumberTheory): seq(`if`(isprime(n), NULL, sigma(n)), n = 1 .. 100); # Reza K Ghazi, Aug 28 2021

Join[{1},DivisorSigma[1,#]&/@Select[Range[100],CompositeQ]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 27 2017 *)

a = List(); for(n=1, 100, if(!isprime(n), listput(a, sigma(n)))); Vec(a) \\ Reza K Ghazi, Aug 28 2021

[sigma(n) for n in range(1, 101) if not is_prime(n)] # Reza K Ghazi Aug 28 2021

a(n) = A000203(A018252(n)).

A162196 Sum of proper divisors minus the number of proper divisors of nonprime number A018252(n).

Original entry on oeis.org

0, 1, 3, 4, 2, 5, 11, 7, 6, 11, 16, 17, 8, 11, 29, 4, 13, 10, 23, 35, 26, 12, 17, 10, 47, 19, 14, 43, 47, 35, 28, 23, 67, 6, 38, 18, 41, 59, 14, 57, 20, 29, 97, 31, 36, 57, 16, 71, 53, 24, 67, 112, 37, 44, 59, 16, 83, 97, 36, 41, 129, 20, 43, 30

Offset: 1

Omar E. Pol, Jul 04 2009

Also, zero together with the positive integers of A152770.

Note that the k-th positive integer of this sequence is equal to the sum of proper divisors minus the number of proper divisors of the composite number A002808(k).

Cf. A001065, A018252, A002808, A032741, A152770, A152988, A152989, A152990, A162194, A162195.

A162196 := proc(n)
        A152770(A018252(n)) ;
end proc: # R. J. Mathar, Sep 28 2011

a(n) = A152770(A018252(n)).

a(n) = A001065(A018252(n)) - A032741(A018252(n)).

cp's OEIS Frontend

A162194 Sum of divisors of nonprime number A018252(n).

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