A proposed solution is listed below for the challenge – Challenge 13 – Generating Digit Product Sequences
Put a starting seed in A1.
Put following formula in A2 and drag down –
=A1+PRODUCT(INDEX(–MID(SUBSTITUTE(A1,0,1),ROW(INDIRECT("1:"&LEN(A1))),1),,))
For a seed value of 1 in A1, it will generate following sequence –
1, 2, 4, 8, 16, 22, 26, 38, 62, 74, 102, 104, 108, 116, 122, 126, 138, 162, 174, 202, 206, 218, 234, 258, 338, 410, 414, 430, 442, 474, 586, 826, 922, 958, 1318, 1342, 1366, …