A083266 Sum of related numbers (counted in A073757) belonging to n: a(n) = A000203(n) + A023896(n) - 1; related = {divisor-set, RRS}.

1, 3, 6, 10, 15, 17, 28, 30, 39, 37, 66, 51, 91, 65, 83, 94, 153, 92, 190, 121, 157, 145, 276, 155, 280, 197, 282, 223, 435, 191, 496, 318, 377, 325, 467, 306, 703, 401, 523, 409, 861, 347, 946, 523, 617, 577, 1128, 507, 1085, 592, 887, 721, 1431, 605, 1171

Offset

1,2

Comments

Sum of 1 <= m <= n such that gcd(m, n) is either 1 or m. - Michael De Vlieger, Apr 07 2021.

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Example

n=10: related terms = {1,2,5,10,3,7,9}, sum = 1+2+5+10+1+3+7+9-1 = 37 = a(10).

Mathematica

Table[DivisorSigma[1, n] + Total@ Select[Range[2, n - 1], GCD[n, #] == 1 &], {n, 55}] (* or *)
{1}~Join~Array[DivisorSigma[1, #] + # EulerPhi[#]/2 - 1 &, 54, 2] (* Michael De Vlieger, Apr 07 2021 *)

Prog

(PARI) a(n)=if(n>1, sigma(n)+n*eulerphi(n)/2-1, 1) \\ Charles R Greathouse IV, Feb 19 2013

Crossrefs

Cf. A073757 (count), A083267 (product), A083268 (lcm).

Sequence in context: A375750 A120993 A194458 * A334130 A054731 A334129

Adjacent sequences: A083263 A083264 A083265 * A083267 A083268 A083269

Keyword

nonn,less

Author

Labos Elemer, May 13 2003

Status

approved