A061423 Sum of digits = 6 times number of digits.
6, 39, 48, 57, 66, 75, 84, 93, 189, 198, 279, 288, 297, 369, 378, 387, 396, 459, 468, 477, 486, 495, 549, 558, 567, 576, 585, 594, 639, 648, 657, 666, 675, 684, 693, 729, 738, 747, 756, 765, 774, 783, 792, 819, 828, 837, 846, 855, 864, 873, 882, 891, 909
Offset: 1
Examples
288 is a term as the arithmetic mean of the digits is (2+8+8)/3 = 6.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
Programs
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Magma
[n: n in [1..1000] | &+Intseq(n) eq 6*#Intseq(n)]; // Vincenzo Librandi, Jan 28 2016
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Maple
F:= proc(m,s) option remember; # list of all m-digit numbers with sum of digits s if s > 9*m or s < 0 then return [] fi; if m = 1 then return [s] fi; [seq(seq(op(map(`+`,procname(j,s-i),10^(m-1)*i)),j=1..m-1),i=1..min(9,s))] end proc: seq(op(F(m,6*m)),m=1..3); # Robert Israel, Jan 27 2016
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Mathematica
Select[Range[1000],Total[IntegerDigits[#]]==6*IntegerLength[#]&] (* Harvey P. Dale, Dec 20 2014 *)
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PARI
isok(n) = {digs = digits(n, 10); return(6*#digs == sum(k=1, #digs, digs[k]));} \\ Michel Marcus, Jul 31 2013
Extensions
More terms from Larry Reeves (larryr(AT)acm.org), May 16 2001