cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A279774 Numbers n such that the sum of digits of 4n equals 8.

Original entry on oeis.org

2, 11, 20, 29, 38, 56, 65, 83, 101, 110, 128, 155, 200, 254, 263, 281, 290, 308, 326, 335, 353, 380, 425, 506, 515, 533, 551, 560, 578, 605, 650, 758, 776, 785, 803, 830, 875, 1001, 1010, 1028, 1055, 1100, 1253, 1280, 1325, 1505, 1550, 1775
Offset: 1

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Author

M. F. Hasler, Dec 23 2016

Keywords

Comments

Inspired by A088406 = A063997/4 and A279769 (the analog for 9).

Crossrefs

Cf. A007953 (digital sum), A279772 (sumdigits(2n) = 4), A279773 (sumdigits(3n) = 6), 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).

Programs

  • Mathematica
    Select[Range@ 2000, Total@ IntegerDigits[4 #] == 8 &] (* Michael De Vlieger, Dec 23 2016 *)
  • PARI
    select( is(n)=sumdigits(4*n)==8, [1..1999])