find sequences

Finds sequences of repeated elements in array

http://simulations.narod.ru/
[i1a i2a]=find_sequences(b,n)
b is 1d array
n is number
finds sequences b==n and return indexes to i1a i2a
all elements b(i1a(i):i2a(i))==n
example:
[i1a i2a]=find_sequences([1 2 2 1 1 1 2 2 2],2)
i1a = 2 7
i2a = 3 9