A077495 a(n) = smallest k such that the digit sum of 8k is n.

0, 125, 25, 15, 5, 4, 3, 2, 1, 9, 8, 7, 6, 23, 22, 12, 11, 37, 36, 62, 61, 87, 86, 112, 111, 236, 361, 486, 611, 736, 861, 986, 1111, 1236, 2486, 3736, 4986, 6236, 7486, 8736, 9986, 11236, 12486, 24986, 37486, 49986, 62486, 74986, 87486, 99986, 112486, 124986

Offset: 0

Author

Amarnath Murthy, Nov 07 2002

Keywords

• base
• nonn

Crossrefs

A069536(n)/8.

Cf. A051885, A069532, A069534, A069536, A077493, A077494.

Programs

Haskell

import Data.List (elemIndex)
import Data.Maybe (fromJust)
a077495 n = fromJust $ elemIndex n $ map a007953 a008590_list
a077495_list = map a077495 [0..]
-- Reinhard Zumkeller, Dec 09 2011

Formula

From Robert Israel, Nov 19 2022: (Start) G.f.: -x^24*(985*x^9 - 125*x^8 - 125*x^7 - 125*x^6 - 125*x^5 - 125*x^4 - 125*x^3 - 125*x^2 - 125*x - 111)/((x - 1)*(10*x^9 - 1)) + 112*x^23 + 86*x^22 + 87*x^21 + 61*x^20 + 62*x^19 + 36*x^18 + 37*x^17 + 11*x^16 + 12*x^15 + 22*x^14 + 23*x^13 + 6*x^12 + 7*x^11 + 8*x^10 + 9*x^9 + x^8 + 2*x^7 + 3*x^6 + 4*x^5 + 5*x^4 + 15*x^3 + 25*x^2 + 125*x.

For n >= 24, a(n) = 125*A051885(n-24) + 111. (End)

Extensions

Corrected and extended by Ray Chandler, Aug 03 2003

Missing a(0)=0 added and offset adjusted by Reinhard Zumkeller, Dec 09 2011