A379098 The waterproof hulls of numbers that are not waterproof (A379097).

180, 252, 360, 396, 468, 504, 612, 684, 720, 792, 828, 1400, 900, 936, 1575, 1008, 1044, 1116, 1224, 6300, 2200, 1332, 1368, 1440, 1476, 2475, 1548, 2600, 4752, 1656, 2800, 1692, 2925, 1764, 1800, 4312, 5616, 3150, 1908, 9900, 2016, 3400, 4851, 2088, 2124, 5096

Offset

1,1

Comments

The waterproof hull h(k) of k is the smallest waterproof number that k divides. Zero and one are waterproof numbers by convention. Numbers that admit a prime factorization are waterproof if their water capacity is 0. (The water capacity of a number is defined in A275339.)

Links

Table of n, a(n) for n=1..46.

Prog

(Python)
# Using function "WaterCapacity" from A275339.
def s(n: int) -> int:
    j = n
    while True:
        if WaterCapacity(j) == 0 and j % n == 0: return j
        j += n
print([s(n) for n in range(1, 700) if WaterCapacity(n) > 0])

Crossrefs

Cf. A275339, A379095, A379096, A379097.

Sequence in context: A378430 A350372 A179643 * A160134 A135193 A095650

Adjacent sequences: A379095 A379096 A379097 * A379099 A379100 A379101

Keyword

nonn

Author

Peter Luschny, Dec 16 2024

Status

approved