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A279772
Numbers n such that the sum of digits of 2n equals 4.
8
2, 11, 20, 56, 65, 101, 110, 155, 200, 506, 515, 551, 560, 605, 650, 1001, 1010, 1055, 1100, 1505, 1550, 2000, 5006, 5015, 5051, 5060, 5105, 5150, 5501, 5510, 5555, 5600, 6005, 6050, 6500, 10001, 10010, 10055, 10100, 10505, 10550, 11000, 15005, 15050, 15500
OFFSET
1,1
COMMENTS
Inspired by A088404 = A069537/2 and A279769 (the analog for 9).
MATHEMATICA
Select[Range@ 15500, Total@ IntegerDigits[2 #] == 4 &] (* Michael De Vlieger, Dec 23 2016 *)
PROG
(PARI) select( is(n)=sumdigits(2*n)==4, [1..9999])
CROSSREFS
Cf. A007953 (digital sum), A052216 (sumdigits(n) = 2), A279773 (sumdigits(3n) = 6), A279774 (sumdigits(4n) = 8), A279775 (sumdigits(5n) = 10), 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: A175927 A116990 A327264 * A226416 A146087 A064975
KEYWORD
nonn,easy,base
AUTHOR
M. F. Hasler, Dec 23 2016
STATUS
approved