Kumar, Nand Kishor, and Raj Kumar Shah. “ Exploring the Symmetry and Relationship Among Harshad Numbers, Fortunate Numbers, Lucky Numbers, and Happy Numbers in Economics”. THE ACADEMIA 6, no. 1 (February 2, 2026): 87–94. Accessed April 9, 2026. https://nepjol.info/index.php/ta/article/view/90323.