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A227238 Numbers whose base-9 sum of digits is 9. 9

%I #26 Jul 10 2022 13:22:33

%S 17,25,33,41,49,57,65,73,89,97,105,113,121,129,137,145,153,169,177,

%T 185,193,201,209,217,225,249,257,265,273,281,289,297,329,337,345,353,

%U 361,369,409,417,425,433,441,489,497,505,513,569,577,585,649,657,737,745

%N Numbers whose base-9 sum of digits is 9.

%C All of the entries are odd.

%C Subsequence of A017077. - _Michel Marcus_, Sep 02 2013

%C In general, the set of numbers with sum of base-b digits equal to b is a subset of { (b-1)*k + 1; k = 2, 3, 4, ... }. - _M. F. Hasler_, Dec 23 2016

%H Michael S. Branicky, <a href="/A227238/b227238.txt">Table of n, a(n) for n = 1..10000</a>

%e The 9-ary expansion of 17 is (1,8), which has sum of digits 9.

%e The 9-ary expansion of 169 is (2,0,7), which has sum of digits 9.

%e 10 is not on the list since the 9-ary expansion of 10 is (1,1), which has sum of digits 2 not 9.

%t Select[Range@ 750, Total@ IntegerDigits[#, 9] == 9 &] (* _Michael De Vlieger_, Dec 23 2016 *)

%o (Sage) [i for i in [0..1000] if sum(Integer(i).digits(base=9))==9]

%o (PARI) select( is(n)=sumdigits(n,9)==9, [1..999]) \\ _M. F. Hasler_, Dec 23 2016

%o (Python)

%o agen = A226636gen(sod=9, base=9) # generator of terms using code in A226636

%o print([next(agen) for n in range(1, 55)]) # _Michael S. Branicky_, Jul 10 2022

%Y Cf. A018900, A187813.

%Y Cf. A226636 (b = 3), A226969 (b = 4), A227062 (b = 5), A227080 (b = 6), A227092 (b = 7), A227095 (b = 8), A227238 (b = 9), A052224 (b = 10).

%K nonn,base,easy

%O 1,1

%A _Tom Edgar_, Sep 01 2013

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Last modified April 23 03:30 EDT 2024. Contains 371906 sequences. (Running on oeis4.)