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A279770
Numbers n such that the sum of digits of 7n equals 14.
8
11, 38, 47, 56, 65, 74, 83, 92, 101, 110, 119, 155, 164, 182, 191, 209, 218, 236, 245, 263, 272, 299, 308, 317, 326, 335, 344, 353, 362, 380, 389, 416, 434, 452, 461, 470, 479, 488, 506, 515, 533, 560, 578, 587, 596, 605, 623, 632, 650, 659, 686, 722, 731
OFFSET
1,1
COMMENTS
Inspired by A088409 = A063416/7 and A279769 (the analog for 9).
MATHEMATICA
Select[Range@ 731, Total@ IntegerDigits[7 #] == 14 &] (* Michael De Vlieger, Dec 23 2016 *)
PROG
(PARI) is(n)=sumdigits(7*n)==14
CROSSREFS
Cf. A007953 (digital sum), A279772 (sumdigits(2n) = 4), A279773 (sumdigits(3n) = 6), A279774 (sumdigits(4n) = 8), A279775 (sumdigits(5n) = 10), A279776 (sumdigits(6n) = 12), 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: A116059 A100842 A057664 * A071853 A072313 A063146
KEYWORD
nonn,easy,base
AUTHOR
M. F. Hasler, Dec 23 2016
STATUS
approved