Palindromic primes: Difference between revisions
→{{header|PARI/GP}}
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</pre>
'''faster'''
<syntaxhighlight lang="parigp">p10( n ) = 10^n;
rew( m, c ) = {
local( t, n );
t = 0; n = m;
for(i=1, c,
t = t*10 + n%10;
n \= 10 );
return( t ) }
range( p, w, disp = 0 ) = {
local( w10, mi, mj, z, pal, q ,k = -1);
w10 = p * p10( w ) + p;
mi = p10( w \ 2 + 1 );
mj = p10( w \ 2 );
z = p10( w \ 2 - 1 ) - 1;
for( i = 0, z,
pal = rew( i, w\2 );
q = w10 + i * mi + pal;
for( j = 0, 9,
if( isprime(q + j * mj ),
k++;
if( disp,
if((k % 8)==0,print());
print1( q + j * mj, "\t") ) ) ) );
return( [ k+1, q + 9*mj ]); }
gener( disp=0 ) = {
local( t=[ 1, 3, 7, 9], s=5, x,start );
start = getabstime();
for( w = 1, 8,
for( i = 1, 20 - 2*w, print1(" "));
print1( p10(w*2));
for( i = 1, 4,
print1(".");
x=range(t[i], w*2, disp);
s+=x[1]; );
printf( "\t # %8d %8.3g [sec]\n",
, s, (getabstime()-start)/1000.0) )
}</syntaxhighlight>
{{out}}
100.... # 20 0.e-19 [sec]
10000.... # 113 0.e-19 [sec]
1000000.... # 781 0.e-19 [sec]
100000000.... # 5953 0.0620 [sec]
10000000000.... # 47995 0.718 [sec]
1000000000000.... # 401696 7.72 [sec]
100000000000000.... # 3438339 86.2 [sec]
=={{header|Perl}}==
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