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 A066956 a(n) = number of ways of placing '+' and '-' among the digits 123456789 so that the result of the expression is n, '-' before 1 not allowed. 3

%I

%S 11,26,11,18,8,21,12,17,8,22,12,21,11,16,15,20,8,17,11,20,15,16,11,23,

%T 18,13,14,21,15,19,17,14,19,19,7,14,19,19,17,18,16,17,18,10,15,26,18,

%U 15,16,12,17,19,9,17,21,16,13,14,16,17,17,11,13,22,14,13,15,15,15,17,7

%N a(n) = number of ways of placing '+' and '-' among the digits 123456789 so that the result of the expression is n, '-' before 1 not allowed.

%C a(n) = 0 for all but finitely many n. In particular, a(n) = 0 for n > 123456789. - _Charles R Greathouse IV_, Aug 20 2012

%H Alois P. Heinz, <a href="/A066956/b066956.txt">Table of n, a(n) for n = 0..34668</a>

%e a(4) = 8 because 4 = 12-34-56-7+89 = 12-3-4-5-6-7+8+9 = 12-3+45-67+8+9 = 12-3+4-5+6+7-8-9 = 12-3+4+5-6-7+8-9 = 12+3-4-5+6-7+8-9 = 12+3-4+5-6-7-8+9 = 1+2-34+5+6+7+8+9 and only for these

%Y Cf. A066957.

%K nice,nonn,base

%O 0,1

%A Miklos SZABO (mike(AT)ludens.elte.hu), Feb 01 2002

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Last modified July 24 11:51 EDT 2021. Contains 346273 sequences. (Running on oeis4.)