A060310 a(1)=1, a(2)=3; then append digits of a(n-1)*a(n).

1, 3, 3, 9, 2, 7, 1, 8, 1, 4, 7, 8, 8, 4, 2, 8, 5, 6, 6, 4, 3, 2, 8, 1, 6, 4, 0, 3, 0, 3, 6, 2, 4, 1, 2, 6, 1, 6, 8, 6, 2, 4, 0, 0, 0, 0, 1, 8, 1, 2, 8, 4, 2, 1, 2, 6, 6, 4, 8, 4, 8, 1, 2, 8, 0, 0, 0, 0, 0, 8, 8, 2, 1, 6, 3, 2, 8, 2, 2, 1, 2, 3, 6, 2, 4, 3, 2, 3, 2, 3, 2, 8, 2, 1, 6, 0, 0, 0, 0, 0, 0, 6, 4, 1, 6

Offset: 1

Author

Jason Earls, Mar 27 2001

Keywords

• nonn
• base

Examples

			1*3=3, 3*3=9, 3*9=27, 9*2=18, ...
		

Links

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

Crossrefs

Cf. A045777, A093094, A093095, A093096, A093097, A096381.

Programs

Mathematica

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

Python

from itertools import islice
from collections import deque
def agen(): # generator of terms
    a = deque([1, 3])
    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