Ans- 263056657646576416441
263056657646576416441
1 (4*1) followed by 1 = 41 (4*41) followed by 41 = 16441 (4*16441) followed by 16441 = **********
similarly next number should be (4***********) followed by ********** = 263056657646576416441
263056657646576416441 i.e. (********** * 4)**********