Odd numbers k that are closer to being perfect than previous terms and also satisfy the conditions that sigma(k) preserves the 3-adic valuation of k, and that sigma(k) == -k (mod 3).
A386420
Odd numbers k that are closer to being perfect than previous terms and also satisfy the conditions that sigma(k) preserves the 3-adic valuation of k, and that sigma(k) == -k (mod 3).
Terms
- a(0) =7a(1) =15a(2) =105a(3) =495a(4) =1365a(5) =2205a(6) =9405a(7) =26145a(8) =31815a(9) =497835a(10) =654675a(11) =1984455a(12) =7188885a(13) =9018009a(14) =9338595a(15) =9958905a(16) =13777785a(17) =13800465a(18) =14571585a(19) =47020995a(20) =78867495a(21) =132884115a(22) =210124665a(23) =363860775a(24) =5784941025a(25) =7637010975a(26) =8616591225a(27) =11555331975a(28) =22857778755
External references
- oeis: A386420