A227241 a(n) = sigma(n)*( 2*sigma(n)+1 ).

3, 21, 36, 105, 78, 300, 136, 465, 351, 666, 300, 1596, 406, 1176, 1176, 1953, 666, 3081, 820, 3570, 2080, 2628, 1176, 7260, 1953, 3570, 3240, 6328, 1830, 10440, 2080, 8001, 4656, 5886, 4656, 16653, 2926, 7260, 6328, 16290, 3570, 18528, 3916, 14196, 12246

Offset

1,1

Comments

If n is prime, then a(n) = (n + 1)*(2n + 3). - Wesley Ivan Hurt, May 14 2021

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

Formula

a(n) = sigma(n)*( 2*sigma(n)+1 ) = A014105(A000203(n)).

Maple

A227241 := proc(n)
    numtheory[sigma](n) ;
    %*(2*%+1) ;
end proc:
seq(A227241(n), n=1..80) ; # R. J. Mathar, Jul 07 2013

Mathematica

Table[DivisorSigma[1, n]*(2*DivisorSigma[1, n] + 1), {n, 1, 50}] (* G. C. Greubel, Oct 01 2017 *)
#(2#+1)&/@DivisorSigma[1, Range[50]] (* Harvey P. Dale, Aug 20 2024 *)

Prog

(PARI) for(n=1, 50, print1(sigma(n)*(2*sigma(n) + 1), ", ")) \\ G. C. Greubel, Oct 01 2017

Crossrefs

Cf. A000203, A005408, A014105.

Sequence in context: A075732 A087690 A191763 * A076169 A298035 A178082

Adjacent sequences: A227238 A227239 A227240 * A227242 A227243 A227244

Keyword

nonn,easy

Author

Wesley Ivan Hurt, Jul 03 2013

Status

approved