From: a boy on
I have a Conjecture: For every n > 1 there is always at least one prime p
such that (n-1)n/2 < p < n(n+1)/2

n = 2; b = 1;
While[NextPrime[b] < (b = n (n + 1)/2), n++]
n

$Aborted

14394105



In this diagram,there is at least one small point(prime) between every two
medium points(triangle number ).

In[58]:= start = 1;
n = 400;
pl = Table[{Prime[i], n}, {i, start, n}];
tl = Table[{i (i + 1)/2, n}, {i, start, n}];
ListLinePlot[Prime[Range[start, n]],
Epilog -> {PointSize[Medium], Point[tl], PointSize[Small], Point[pl]}]


The still unsolved Legendre's conjecture asks whether for every n > 1, there
is a prime p, such that n^2 < p < (n + 1)^2. Comparing,

(n+1)^2-n^2=2n+1, while n(n+1)/2-(n-1)n/2=n


From: a boy on
Clear[n];
FindInstance[ NextPrime[n (n - 1)/2] > n (n + 1)/2 && 0 < n <
2^2^20, {n}, Integers]

FindInstance::nsmet: The methods available to FindInstance are
insufficient to find the requested instances or prove they do not
exist.

On Feb 1, 7:13 pm, a boy <a.dozy....(a)gmail.com> wrote:
> I have a Conjecture: For every n > 1 there is always at least one prime p
> such that (n-1)n/2 < p < n(n+1)/2
>
> n = 2; b = 1;
> While[NextPrime[b] < (b = n (n + 1)/2), n++]
> n
>
> $Aborted
>
> 14394105
>
> In this diagram,there is at least one small point(prime) between every tw=
o
> medium points(triangle number ).
>
> In[58]:= start = 1;
> n = 400;
> pl = Table[{Prime[i], n}, {i, start, n}];
> tl = Table[{i (i + 1)/2, n}, {i, start, n}];
> ListLinePlot[Prime[Range[start, n]],
> Epilog -> {PointSize[Medium], Point[tl], PointSize[Small], Point[pl]}]
>
> The still unsolved Legendre's conjecture asks whether for every n > 1, th=
ere
> is a prime p, such that n^2 < p < (n + 1)^2. Comparing,
>
> (n+1)^2-n^2=2n+1, while n(n+1)/2-(n-1)n/2=n