is_prime, a Fortran90 code which implements various versions of the sieve of Eratosthenes to determine whether a given integer is prime.
The computer code and data files made available on this web page are distributed under the MIT license
is_prime is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version.
i4lib, a Fortran90 code which contains many utility routines, using integer arithmetic.
polpak, a Fortran90 code which evaluates a variety of mathematical functions, polynomials, and sequences, including Bell, Benford, Bernoulli, Bernstein, Cardan, Catalan, Charlier, Chebyshev, Collatz, Delannoy, Euler, Fibonacci, Gegenbauer, Gudermannian, Harmonic, Hermite, Hofstadter, Jacobi, Krawtchouk, Laguerre, Lambert, Legendre, Lerch, Meixner, Mertens, Moebius, Motzkin, Phi, Stirling, Tau, Tribonacci, Zernike.