python program to print bell number

bell_number.py

@@ -0,0 +1,22 @@
+#Python program to print bell number
+#Bell Number:-Let S(n, k) be total number of partitions of n elements into k sets. The value of n’th Bell Number is sum of S(n, k) for k = 1 to n. Value of S(n, k) can be defined recursively as, S(n+1, k) = k*S(n, k) + S(n, k-1)
+A sample Bell triangle is as follows:
+1
+1   3
+3   8   13
+13  23  33  43
+#The code to print the bell triangle is as follows-
+#---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+n=int(input("enter the number of bell"))     #taking value from the user
+bell=0                                       #initialising bell to 'zero'
+k=0                                          #initialising k to 'zero'
+for i in range(0,n):                         #loop for changing rows from 0 to n
+    for j in range(0,i+1):                   #printing columns
+        if j==0 and i>0:                     #repeating the last number of previous row in new row
+            print(bell,'',end='')            #printing first number of each line
+        else:
+            k=(i**2)+1+bell                  #to generate other numbers of line
+            print(k,'',end='')               #printing other number in lines
+            bell=k                           #updating value of bell 
+    print('\n')                              #for moving into next lines           
+print("last number of bell is",bell)