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

11, 29, 38, 47, 56, 65, 74, 83, 92, 101, 110, 128, 146, 164, 182, 209, 218, 227, 236, 245, 254, 263, 272, 281, 290, 308, 326, 344, 362, 380, 407, 416, 425, 434, 443, 452, 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

Offset

1,1

Comments

Inspired by A088407 = A069540/5 and A279769 (the analog for 9).

Links

Michael S. Branicky, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range@ 920, Total@ IntegerDigits[5 #] == 10 &] (* Michael De Vlieger, Dec 23 2016 *)

Prog

(PARI) select( is(n)=sumdigits(5*n)==10, [0..999])
(Python)
def ok(n): return sum(map(int, str(5*n))) == 10
print([k for k in range(921) if ok(k)]) # Michael S. Branicky, Nov 29 2021

Crossrefs

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).

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.

Cf. A005349 (Niven or Harshad numbers), A245062 (arranged in rows by digit sums).

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).

Sequence in context: A360181 A092194 A134307 * A211191 A353043 A350420

Adjacent sequences: A279772 A279773 A279774 * A279776 A279777 A279778

Keyword

nonn,easy,base

Author

M. F. Hasler, Dec 23 2016

Status

approved