Question

first five number of:

a) Palindromic numbers

b) Triangular numbers

c) Square numbers

Answer 1

Palindromic numbers , depends on what you want,
single digit numbers: 1 2 3 4 5
double digit numbers: 11 22 33 44 55
triple digit numbers: 111 121 131 141 151

Triangular numbers:
look at the number of billiard balls that can be placed in the standard triangle used in billiards
number of balls in first row -- 1
number of balls in first two rows --- 3
number of balls in first 3 rows ----- 6
number of balls in first 4 rows ----- 10
number of balls in first 5 rows ----- 15
So: 1 3 6 10 15

square numbers: 1 4 9 16 25