A212610 Pairs of primitive deficient numbers having the same value of sigma(k)/k, listed by increasing value of the larger of the two k values.

135, 819, 3375, 6975, 25137, 40131, 68607, 154791, 22113, 448335, 557375, 721525, 451737, 1401543, 1278316, 1680705, 273, 2876211, 6739509, 10590125, 188325, 11208375, 8775, 12525435, 9020375, 13934375, 20365625, 56162575, 1083537, 83479977, 3416875

Offset: 1

Author

T. D. Noe, May 23 2012

Keywords

• nonn

Comments

"Primitive" means that the pair (a(2n-1),a(n)) = (k,k') is not a multiple of another such pair occurring earlier. - M. F. Hasler, Feb 25 2013

Links

• Donovan Johnson, Table of n, a(n) for n = 1..48

Crossrefs

Cf. A211680 (non-primitive pairs), A212611, A212612 (the pairs separated).

Formula

a(2n-1) = A212611(n), a(2n) = A212612(n), for all n>0. - M. F. Hasler, Feb 22 2013

Extensions

a(19)-a(31) from Donovan Johnson, May 24 2012