A188226 Smallest number having exactly n divisors of the form 8*k + 7.

1, 7, 63, 315, 945, 1575, 3465, 19845, 10395, 17325, 26775, 127575, 45045, 266805, 190575, 155925, 135135, 2480625, 225225, 130203045, 405405, 1289925, 2168775, 1715175, 675675, 3898125, 3468465, 1576575, 3239775, 67798585575, 2027025, 16769025, 2297295, 20539575, 42170625, 27286875, 3828825, 117661005

Offset: 0

Author

Reinhard Zumkeller, Mar 26 2011

Keywords

• nonn

Comments

A188172(a(n)) = n and A188172(m) <> n for m < a(n).

Links

• Bert Dobbelaere, Table of n, a(n) for n = 0..200

Crossrefs

Cf. A004771, A141164, A188172.

Smallest number having exactly n divisors of the form 8*k + i: A343104 (i=1), A343105 (i=3), A343106 (i=5), this sequence (i=7).

Programs

Haskell

import Data.List  (elemIndex)
import Data.Maybe (fromJust)
a188226 n = a188226_list !! n
a188226_list =
   map (succ . fromJust . (`elemIndex` (map a188172 [1..]))) [0..]

Extensions

a(19)-a(35) from Nathaniel Johnston, Apr 06 2011

More terms from Bert Dobbelaere, Apr 09 2021