def solve():
minD = 10**10
j = 1
while True:
j += 1
p_j = pentagonal_number(j)
#p_k < p_j
k_start = find_pentagonal_index_below(max(1, p_j - minD)) + 1
# choose start such that: |p_j - p_k_start |< minD
if p_j - pentagonal_number(j-1) > minD:
break
for k in range(k_start, j):
p_k = pentagonal_number(k)
diff = p_j - p_k
if diff < minD and is_pentagonal_number(diff) and is_pentagonal_number(p_k + p_j):
minD = diff
print(minD, k, j)
print("The minimal value for D is %(minD)d" % vars())
def solve(T):
return find_first(lambda n: is_pentagonal_number(n) and is_hexagonal_number(n) and n > T, triangulars())
