OFFSET
1,12
COMMENTS
Digits, not terms!
There are only 10^10 possibilities for the last 10 digits, so the sequence must eventually cycle.
Cycles at n(19) = 44 and the loop has 312 terms. - Hans Havermann
Terms computed by Gilles Sadowski.
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..331 (through first loop)
EXAMPLE
0 + 0 + 1 + 1 + 2 + 4 + 8 + 1 + 6 = 23
MATHEMATICA
a[1] = a[2] = a[3] = a[4] = a[5] = a[6] = a[7] = a[8] = a[9] = 0; a[10] = 1; a[n_] := a[n] = Plus @@ Take[ Flatten@Table[IntegerDigits[a[i]], {i, n - 10, n - 1}], -10]; Array[a, 74] (* Robert G. Wilson v, Dec 09 2005 *)
PROG
(Python)
from itertools import islice
def agen(): # generator of terms
last10 = [0, 0, 0, 0, 0, 0, 0, 0, 0, 1]
print(last10[:0])
yield from last10
while True:
an = sum(last10)
yield an
d = list(map(int, str(an)))
last10 = last10[-max(10-len(d), 0):] + d[-min(len(d), 10):]
print(list(islice(agen(), 74))) # Michael S. Branicky, Oct 03 2024
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Eric Angelini, Dec 05 2005
STATUS
approved