OFFSET
1,2
COMMENTS
The subsequence of multiples of 11 begins: 0, 11, 22, 33, 44, 55, 66, 77, 88, 99, 110, 220, 330, 440...
The subsequence of primes begins: 11, 101, 211, 431, 523, 541, 743, 761, 853, ... (see A156307).
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
If decimal expansion of n is x1 x2 ... xk then x1 - x2 - ... - xk = 0.
MAPLE
V:= proc(n, s) # n-digits numbers with sum of digits s
option remember; local i, k;
`union`(seq(seq(map(t -> i*10^(n-1) + t, procname(k, s-i)), k=1..n-1), i=1..min(s, 9)))
end proc:
for s from 0 to 9 do V(1, s) := {s} od:
f:= proc(n) local s, k;
`union`(seq(seq(map(t -> s*10^(n-1) + t, V(k, s)), k=1..n-1), s=1..9))
end proc:
sort(convert(`union`(seq(f(d), d=1..4)), list)); # Robert Israel, Nov 14 2024
MATHEMATICA
fQ[n_] := Module[{d = IntegerDigits[n]}, d[[1]] == Total[Rest[d]]]; Select[Range[0, 1000], fQ] (* T. D. Noe, Jan 02 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Dario Piazzalunga, Jan 02 2013
EXTENSIONS
Definition edited by Michel Marcus, Oct 26 2014
STATUS
approved