Calmo numbers: Difference between revisions

=={{header|PARI/GP}}==

<syntaxhighlight lang="PARI/GP">

\\ Function to get the divisors of a number excluding 1 and the number itself

eligibleDivisors(n) = {

my(divs = divisors(n)); \\ Compute all divisors of n

if (#divs <= 2, return([])); \\ If there are no divisors other than 1 and n, return an empty list

vecextract(divs, "2..-2"); \\ Extract divisors without the first and last elements (1 and n)

};

\\ Function to check if the sum of every three consecutive eligible divisors is prime

isCalmoNumber(n) = {

my(divisors, sums, i, k);

divisors = eligibleDivisors(n); \\ Get eligible divisors

if ((#divisors % 3 != 0) || (#divisors == 0), return(0)); \\ If not divisible by 3 or no divisors, return false

sums = vector(#divisors \ 3, i, sum(k = 1, 3, divisors[3*i + k - 3])); \\ Compute sums of every three divisors

for (i = 1, #sums,

if (!isprime(sums[i]), return(0)); \\ If any sum is not prime, return false

);

return(1); \\ If all sums are prime, return true

};

{

\\ Find all Calmo numbers under 1000

calmoNumbers = [];

for (n = 1, 1000,

if (isCalmoNumber(n), calmoNumbers = concat(calmoNumbers, n)); \\ Check if n is a Calmo number and add to the list

);

print(calmoNumbers); \\ Print all Calmo numbers found under 1000

}

</syntaxhighlight>

{{out}}

<pre>

[165, 273, 385, 399, 561, 595, 665, 715, 957]

</pre>