Challenge No. 344: List all Katadrome numbers.
Solved using: Python in Excel.
SEQUENCE
Generates a sequence of numbers in an array in Excel.
Find nearest Palindrome numbers
Challenge No. 343: Palindrome number is that which is same even when read backwards.
Solved using: R.
List valid South African National IDs
Challenge No. 342: List the valid South African National IDs (person identification numbers).
Solved using: Python in Excel.
Sort odd positioned numbers
Challenge No. 341: Sort the numbers at odd positions.
Solved using: Python in Excel.
Calculate check digit using Damm algorithm
Challenge No. 338: Calculate check digit using Damm algorithm.
Solved using: Python in Excel.
Count of numbers where digits’ product equals value
Challenge No. 337: Find the Min, Max and Count of numbers having number of digits in column A whose product of digits is equal to column B.
Solved using: R.
Matrix Calculation! Part 2
Challenge No. 198: Create a formula that, for any ‘n x n’ matrix, calculates z1 to zn, where zi is the sum of all the values in the ith row and the ith column of the matrix.
Solved using:Excel (BYCOL, INDEX, LAMBDA), Google Sheets, Power Query (List.Transform, Table.FromRows, Table.ToColumns), Python, Python in Excel, and R.
Decrypt using 5×76 transposition cipher
Challenge No. 335: This is a 5 x 76 transposition cipher, where you start with the letter in the final position (‘W’) and then repeatedly step back through the whole ciphertext 5 positions at a time time, and then repeat that same process but starting from the letter one before the last position (‘T’) etc, revealing the first words of Geoffrey Chaucer’s ‘Canterbury Tales’.
Solved using: Python in Excel.
Custom Grouping! Part 19
Challenge No. 197: Group the rows sequentially from the top, ensuring that each group contains exactly one missing date.
Solved using:Excel (IF, LET, SCAN), Google Sheets, Power Query (Table.Group, Table.AddIndexColumn), Python, Python in Excel, and R.
List all Amicable numbers
Challenge No. 334: List the Amicable numbers.
Solved using: Python in Excel.