create a matrix that keeps only the sequential numbers

Hi! I need to create a matrix that keeps only the sequential numbers in the first column (and keep the corresponding number in the second column) and delete everything else. Here is an example:

[Stephen23]

What should happen if there are two or more series of sequential numbers?

[Akira Agata]

What happens if the 1st column consists of two sequential numbers, like: [1 2 3 4 7 8 9 10]' ?

[Alberto Acri]

@Stephen23 If there are two or more sets of sequential numbers, I would like to keep all sequences of at least 2 sequential numbers. So if the first column is: [77; 78; 79; 81; 83; 84; 94] it would become: [77; 78; 79; 83; 84]. Or if the first column is: [77; 78; 79; 81; 82; 83; 84] it would remain the same.

@Akira Agata In the case you wrote, the column would remain the same.

Answer 1

[Stephen23]

S = load('CountArray_A_zoom_select.mat');
A = S.CountArray_A_zoom_select

A = 9×2

77 769 78 513 79 412 80 331 81 297 82 182 83 116 84 76 94 64

X = diff(A(:,1))==1;
Y = [X;0]|[0;X];
B = A(Y,:)

B = 8×2

77 769 78 513 79 412 80 331 81 297 82 182 83 116 84 76