cp's OEIS Frontend

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

%I A077495 #15 Nov 19 2022 20:18:15
%S A077495 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,
%T A077495 236,361,486,611,736,861,986,1111,1236,2486,3736,4986,6236,7486,8736,
%U A077495 9986,11236,12486,24986,37486,49986,62486,74986,87486,99986,112486,124986
%N A077495 a(n) = smallest k such that the digit sum of 8k is n.
%F A077495 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.
%F A077495 For n >= 24, a(n) = 125*A051885(n-24) + 111. (End)
%o A077495 (Haskell)
%o A077495 import Data.List (elemIndex)
%o A077495 import Data.Maybe (fromJust)
%o A077495 a077495 n = fromJust $ elemIndex n $ map a007953 a008590_list
%o A077495 a077495_list = map a077495 [0..]
%o A077495 -- _Reinhard Zumkeller_, Dec 09 2011
%Y A077495 A069536(n)/8.
%Y A077495 Cf. A051885, A069532, A069534, A069536, A077493, A077494.
%K A077495 base,nonn
%O A077495 0,2
%A A077495 _Amarnath Murthy_, Nov 07 2002
%E A077495 Corrected and extended by _Ray Chandler_, Aug 03 2003
%E A077495 Missing a(0)=0 added and offset adjusted by _Reinhard Zumkeller_, Dec 09 2011