Category Archives: Uncategorized

Imagemagick showcolor() { display -size 300×300 xc:”#${1}”; } showcolor fba9c3 &

Generate magic squares for any odd side length: #!/usr/bin/env python3 import sys def magic_constant(n): return n * (n * n + 1) // 2 def magic_square(n): square = [[0] * n for _ in range(n)] num = 1 i, j … Continue reading →

Print a list of last Fridays every month for the given year #!/usr/bin/python3 import sys from calendar import monthrange from datetime import date, timedelta def last_fridays(year): for month in range(1, 13): last_day = date(year, month, monthrange(year, month)[1]) yield last_day – … Continue reading →

Perfect #include <stdio.h> int main(void) { for (unsigned int p = 2; p <= 23; p++) { unsigned long long m = (1ULL << p) – 1; int prime = 1; for (unsigned long long i = 2; i * … Continue reading →

Print a list of antiprimes (highly composite numbers) with bc #! /usr/bin/bc define factors(n) { auto c, i for(i=1;i<=n;i++) { if(n%i==0) c+=1 } return c } max = 0 n = 1 for(c=19; c > 0;) { f = factors(n) … Continue reading →

Combinations of r elements chosen from a pool of n elements BEGIN { for (i=1; i <= r; i++) { A[i] = i if (i < r ) printf i OFS else print i} while (A[1] < n – r … Continue reading →

Hex #!/usr/bin/python3 import sys with open(sys.argv[1], “rb”) as f: data = f.read() for offset in range(0, len(data), 16): b = data[offset:offset + 16] left = ” “.join(f”{x:02x}” for x in b[:8]) right = ” “.join(f”{x:02x}” for x in b[8:]) hexpart … Continue reading →

scale=90 for (e = n = f = 1; f != 0; f /= ++n) e += f e

Palindromic primes 20 FOR N=2 TO 100000 30 I=N 35 J=0 40 J=J*10+I-INT(I/10)*10 43 I=INT(I/10) 47 IF I>0 THEN 40 50 IF J<>N THEN 80 52 IF N=2 THEN 75 60 FOR I=2 TO SQR(N) 65 IF N-INT(N/I)*I=0 THEN 80 … Continue reading →

Palindate #! /bin/bash is_palyndrom_date() { date -d “$1” 1>/dev/null 2>&1 && echo “$1” ; } for _H in {2..9}; do for _I in {0..9}; do for _J in {0..99}; do is_palyndrom_date ${_H}${_I}`printf “%02d%s” ${_J}`-`printf “%02d%s” ${_J} | rev`-`printf “%02d%s” ${_H}${_I} | … Continue reading →