A226586 Odd values of sigma(n) - phi(n) in the order of appearance and with repetition.

5, 11, 7, 23, 33, 11, 47, 79, 15, 73, 95, 171, 67, 129, 177, 23, 191, 355, 309, 27, 315, 385, 283, 289, 383, 723, 35, 739, 393, 39, 687, 801, 489, 1089, 711, 767, 47, 1459, 649, 281, 1599, 969, 801, 607, 1431, 1633, 59, 1971, 2581, 63, 1555, 1535, 1153, 1069, 2931, 1605, 927, 1843, 3319, 2121

Offset

1,1

Comments

Odd values of A051612(n) sorted along n.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Formula

sigma(4) - phi(4) = 7 - 2 = 5. Since 5 is the first odd value of sigma(n) - phi(n), it appears first in the list. So a(1) = 5.

Maple

select(type, [seq(numtheory:-sigma(n)-numtheory:-phi(n), n=1..2000)], odd); # Robert Israel, Aug 11 2019

Mathematica

Select[Table[DivisorSigma[1, n]-EulerPhi[n], {n, 2000}], OddQ] (* Harvey P. Dale, Sep 27 2013 *)

Crossrefs

Cf. A051612, A028982.

Sequence in context: A226619 A367705 A068419 * A368055 A358613 A329005

Adjacent sequences: A226583 A226584 A226585 * A226587 A226588 A226589

Keyword

nonn

Author

Wesley Ivan Hurt, Jun 28 2013

Status

approved