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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Inspired by A088404 = A069537/2 and A279769 (the analog for 9).

LINKS

Table of n, a(n) for n=1..45.

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: A092595 A175927 A116990 * A226416 A146087 A064975

Adjacent sequences:  A279769 A279770 A279771 * A279773 A279774 A279775

KEYWORD

nonn,easy,base

AUTHOR

M. F. Hasler, Dec 23 2016

STATUS

approved

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Last modified April 19 09:11 EDT 2019. Contains 322241 sequences. (Running on oeis4.)