Consider two sequences (ai)iN and (bi)iZ+. When ai=i+1 and bi=i, the two sequences are equal and the first terms are 1,2,3,4,5, Likewise, find explicit formulas for ai and bi such that the two sequences are equal and the first terms are: a) 7,11,15,19,23, b) 3,6,12,24,48, c) 0,11,99,1001,9999, d) 1,0,3,0,5,0,7,0