Function carmichaelLambda

src/compute-engine/library/number-theory.ts:1288–1303

Carmichael's reduced totient λ(n) from the prime factorization (`n ≥ 1`).

(n: bigint)

        const seen = new Set<bigint>();
        let k = toBigint(n);
        // Happy numbers are positive integers; a negative `k` would also make
        // `sumSquareDigits` throw on the "-" sign.
        if (k === null || k < 1n) return ce.False;
        while (!seen.has(k)) {
          if (k === 1n) return ce.True;
          seen.add(k);
          k = sumSquareDigits(k);
        }
        return ce.False;
      },
    },

    IsAbundant: {
      description: 'True if n is an abundant number (sum of divisors > 2n).',
      signature: '(integer) -> boolean',
      evaluate: ([n], { engine: ce }) => {
        const k = toBigint(n);
        if (k === null || k < 1n) return ce.False;
        let sum = 1n;