A365507 - OEIS

A365507

a(n) is the least positive integer that can be expressed as the sum of one or more consecutive n-almost primes in exactly n ways, or -1 if no such integer exists.

%I #6 Sep 25 2023 09:07:25

%S 2,10,105,2410,45010,708408

%N a(n) is the least positive integer that can be expressed as the sum of one or more consecutive n-almost primes in exactly n ways, or -1 if no such integer exists.

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/AlmostPrime.html">Almost Prime</a>.

%e For n = 3: 105 = 3*5*7 = 2*2*3 + 2*3*3 + 2*2*5 + 3*3*3 + 2*2*7 = 2*2*5 + 3*3*3 + 2*2*7 + 2*3*5.

%Y Cf. A054859, A091538, A186337.

%K nonn,more

%O 1,1

%A _Ilya Gutkovskiy_, Sep 07 2023