# Euler problems/141 to 150

From HaskellWiki

## Contents

## Problem 141

Investigating progressive numbers, n, which are also square.

Solution:

```
problem_141 = undefined
```

## Problem 142

Perfect Square Collection

Solution:

```
problem_142 = undefined
```

## Problem 143

Investigating the Torricelli point of a triangle

Solution:

```
problem_143 = undefined
```

## Problem 144

Investigating multiple reflections of a laser beam.

Solution:

```
problem_144 = undefined
```

## Problem 145

How many reversible numbers are there below one-billion?

Solution:

```
problem_145 = undefined
```

## Problem 146

Investigating a Prime Pattern

Solution:

```
problem_146 = undefined
```

## Problem 147

Rectangles in cross-hatched grids

Solution:

```
problem_147 = undefined
```

## Problem 148

Exploring Pascal's triangle.

Solution:

```
problem_148 = undefined
```

## Problem 149

Searching for a maximum-sum subsequence.

Solution:

```
problem_149 = undefined
```

## Problem 150

Searching a triangular array for a sub-triangle having minimum-sum.

Solution:

```
problem_150 = undefined
```