A372815 The square of n minus (the largest divisor d of n with 2 <= d <= m-1, or 0 if there is no such divisor).
1, 4, 9, 14, 25, 33, 49, 60, 78, 95, 121, 138, 169, 189, 220, 248, 289, 315, 361, 390, 434, 473, 529, 564, 620, 663, 720, 770, 841, 885, 961, 1008, 1078, 1139, 1218, 1278, 1369, 1425, 1508, 1580, 1681, 1743, 1849, 1914, 2010, 2093, 2209, 2280, 2394, 2475, 2584
Offset: 1
Keywords
Examples
For n = 10, the divisors of n are {1,2,5,10}. The largest nontrivial divisor is 5, so 10 * 10 - 5 = 95.
Crossrefs
Programs
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Mathematica
Table[ Module[{divisors, largestNonTrivialDivisor}, divisors = Divisors[n]; largestNonTrivialDivisor = If[Length[divisors] > 2, divisors[[-2]], 0]; n^2 - largestNonTrivialDivisor ], {n, 1, 20} ] -
Python
def factors(n): return sorted([i for i in range(2, n - 1) if n % i == 0]) def main(): for i in range(1, 20): fs = factors(i) if len(fs) == 0: l = 0 else: l = fs[-1] print(i*i - l) if _name_ == "_main_": main()