A302599 Numbers k such that digit_sum(k) > digit_sum(2k).

5, 6, 7, 8, 15, 16, 17, 25, 26, 35, 50, 51, 52, 53, 55, 56, 57, 58, 59, 60, 61, 62, 65, 66, 67, 68, 69, 70, 71, 75, 76, 77, 78, 79, 80, 85, 86, 87, 88, 89, 95, 96, 97, 98, 105, 106, 107, 115, 116, 125, 150, 151, 152, 155, 156, 157, 158, 159, 160, 161, 165, 166

Offset

1,1

Comments

Conjecture: a(n) ~ 2n. - Charles R Greathouse IV, Apr 10 2018

If n is in the sequence then so is 10*n. - David A. Corneth, Apr 10 2018

a(10^9) = 2367976531. - Charles R Greathouse IV, Apr 11 2018

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

17 is in this sequence because 1+7 > 3+4.

Maple

select(t -> convert(convert(2*t, base, 10), `+`)<convert(convert(t, base, 10), `+`), [$1..1000]); # Robert Israel, Apr 12 2018

Mathematica

With[{s = Array[Total@ IntegerDigits@ # &, 332]}, Select[Range@ Floor[Length[s]/2], s[[#]] > s[[2 #]] &]] (* Michael De Vlieger, Apr 10 2018 *)

Prog

(Python)
print([y for y in range(10000) if sum([int(x) for x in str(y)]) > sum([int(z) for z in str(2*y)])])
(PARI) is(n)=sumdigits(n)>sumdigits(2*n) \\ Charles R Greathouse IV, Apr 10 2018

Crossrefs

Cf. A004092, A007953, A070279.

Sequence in context: A014097 A219331 A229862 * A098670 A343570 A320021

Adjacent sequences: A302596 A302597 A302598 * A302600 A302601 A302602

Keyword

nonn,base,easy

Author

David Consiglio, Jr., Apr 10 2018

Status

approved