Idoneal numbers: Difference between revisions

=={{header|Action!}}==

<syntaxhighlight lang="action!">

;;; find idoneal numbers - numbers that cannot be written as ab + bc + ac

;;; where 0 < a < b < c

;;; there are 65 known idoneal numbers

PROC Main()

CARD count, maxCount, n, n2, a, b, c, ab, sum

BYTE idoneal

count = 0 maxCount = 65

n = 0

n2 = n - 2 ; n2 will be 65534 = -2

WHILE count < maxCount DO

n ==+ 1

n2 ==+ 1

idoneal = 1

a = 0

DO

a ==+ 1

IF a >= n2 THEN

EXIT

ELSEIF idoneal = 0 THEN

EXIT

ELSE

b = a + 1

DO

ab = a * b

IF ( ab + a + b ) > n OR idoneal = 0 THEN EXIT FI

c = b + 1

DO

sum = ab + ( b * c ) + ( a * c )

IF sum = n THEN

idoneal = 0

EXIT

ELSEIF sum > n THEN

EXIT

ELSE

c ==+ 1

FI

OD

b ==+ 1

OD

FI

OD

IF idoneal THEN

Put(' )

IF n < 10 THEN Put(' ) FI

IF n < 100 THEN Put(' ) FI

IF n < 1000 THEN Put(' ) FI

PrintC( n )

count ==+ 1

IF count MOD 13 = 0 THEN PutE() FI

FI

OD

RETURN

</syntaxhighlight>

{{out}}

<pre>

1 2 3 4 5 6 7 8 9 10 12 13 15

16 18 21 22 24 25 28 30 33 37 40 42 45

48 57 58 60 70 72 78 85 88 93 102 105 112

120 130 133 165 168 177 190 210 232 240 253 273 280

312 330 345 357 385 408 462 520 760 840 1320 1365 1848

</pre>