cp's OEIS Frontend

A279775 Numbers k such that the sum of digits of 5k equals 10.

%I A279775 #18 Nov 29 2021 20:34:51
%S A279775 11,29,38,47,56,65,74,83,92,101,110,128,146,164,182,209,218,227,236,
%T A279775 245,254,263,272,281,290,308,326,344,362,380,407,416,425,434,443,452,
%U A279775 461,470,488,506,524,542,560,605,614,623,632,641,650,668,686,704,722,740,803,812,821,830,848,866,884,902,920
%N A279775 Numbers k such that the sum of digits of 5k equals 10.
%C A279775 Inspired by A088407 = A069540/5 and A279769 (the analog for 9).
%H A279775 Michael S. Branicky, <a href="/A279775/b279775.txt">Table of n, a(n) for n = 1..10000</a>
%t A279775 Select[Range@ 920, Total@ IntegerDigits[5 #] == 10 &] (* _Michael De Vlieger_, Dec 23 2016 *)
%o A279775 (PARI) select( is(n)=sumdigits(5*n)==10, [0..999])
%o A279775 (Python)
%o A279775 def ok(n): return sum(map(int, str(5*n))) == 10
%o A279775 print([k for k in range(921) if ok(k)]) # _Michael S. Branicky_, Nov 29 2021
%Y A279775 Cf. A007953 (digital sum), A279772 (sumdigits(2n) = 4), A279773 (sumdigits(3n) = 6), A279774 (sumdigits(4n) = 8), A279776 (sumdigits(6n) = 12), A279770 (sumdigits(7n) = 14), A279768 (sumdigits(8n) = 16), A279769 (sumdigits(9n) = 18), A279777 (sumdigits(9n) = 27).
%Y A279775 Digital sum of m*n equals m: A088404 = A069537/2, A088405 = A052217/3, A088406 = A063997/4, A088407 = A069540/5, A088408 = A062768/6, A088409 = A063416/7, A088410 = A069543/8.
%Y A279775 Cf. A005349 (Niven or Harshad numbers), A245062 (arranged in rows by digit sums).
%Y A279775 Numbers with given digital sum: A011557 (1), A052216 (2), A052217 (3), A052218 (4), A052219 (5), A052220 (6), A052221 (7), A052222 (8), A052223 (9), A052224 (10), A166311 (11), A235151 (12), A143164 (13), A235225 (14), A235226 (15), A235227 (16), A166370 (17), A235228 (18), A166459 (19), A235229 (20).
%K A279775 nonn,easy,base
%O A279775 1,1
%A A279775 _M. F. Hasler_, Dec 23 2016