A093097 Start with a(1) = 3, a(2) = 7; then apply the rule of A093094.

3, 7, 2, 1, 1, 4, 2, 1, 4, 8, 2, 4, 3, 2, 1, 6, 8, 1, 2, 6, 2, 6, 4, 8, 8, 2, 1, 2, 1, 2, 1, 2, 2, 4, 3, 2, 6, 4, 1, 6, 2, 2, 2, 2, 2, 2, 4, 8, 1, 2, 6, 1, 2, 2, 4, 4, 6, 1, 2, 4, 4, 4, 4, 4, 8, 3, 2, 8, 2, 1, 2, 6, 2, 4, 8, 1, 6, 2, 4, 6, 2, 8, 1, 6, 1, 6, 1, 6, 1, 6, 3, 2, 2, 4, 6, 1, 6, 1, 6, 2, 2, 1, 2, 1, 2

Offset: 1

Author

Bodo Zinser, Mar 20 2004

Keywords

• nonn
• base

Examples

			a(3)=first digit of (a(1)*a(2)), a(4)=2nd digit of (a(1)*a(2)), a(5)=first digit of (a(2)*a(3)), a(6)=2nd digit of (a(2)*a(3))
		

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A045777, A060310, A093094, A093095, A093096, A096381.

Programs

Mathematica

Fold[Join[#, IntegerDigits[Times @@ #[[#2;; #2+1]]]] &, {3, 7}, Range[100]] (* Paolo Xausa, Aug 18 2025 *)

Python

from itertools import islice
from collections import deque
def agen(): # generator of terms
    a = deque([3, 7])
    while True:
        a.extend(list(map(int, str(a[0]*a[1]))))
        yield a.popleft()
print(list(islice(agen(), 105))) # Michael S. Branicky, Aug 18 2025