Question

1,3,7,25,103,? Complete the missing term

Answer 1

The Difference of numbers is a sequence of
  2 4 18 78 ...
Their difference terms are
  0,2,14,60
Each Term differs from powers of 2 and add by their differences by
$2^{1}+0,2^{1}+2,2^{4}+2,2^{6}+14,2^{7}+14$
so The answer is
$2^7+14+103=245$
  

Answer 2

1,3,7,25,103. , 1×1+2=3. , 3×2+1=7. , 7×3+4=25. , 25×4+3=103. , 103×5+6=521. , So observe any pattern Well see then the pattern is . 1×n+ (n±1). Where n belongs to the set (1,2,3,4..........infinity) Now if n is odd then we add +1 to that number And if it is even then we subtract one So the next term will be 521×6+(6-1)=3131 Thank-you for this question... I really like it