login
A375078
a(1)=1; thereafter a(n) is the number of digits in (n mod 10) already present in the sequence.
1
1, 0, 0, 0, 0, 0, 0, 0, 0, 8, 1, 0, 0, 0, 0, 0, 0, 1, 0, 15, 4, 0, 0, 1, 1, 0, 0, 1, 0, 20, 7, 1, 0, 1, 1, 0, 1, 1, 0, 24, 12, 3, 1, 2, 1, 0, 1, 1, 0, 26, 17, 5, 1, 2, 2, 1, 2, 1, 0, 27, 21, 10, 1, 2, 2, 1, 3, 1, 0, 29, 26, 14, 2, 3, 2, 2, 3, 1, 1, 29, 29, 19
OFFSET
1,10
LINKS
Paolo P. Lava, First 1000 terms
Carlos Rivera, Puzzle 1182. Another sequence by Paolo Lava, The Prime Puzzles and Problems Connection.
MAPLE
P:=proc(q) local a, b, c, n; a:=[1]; b:=[1];
for n from 2 to q do c:=numboccur(n mod 10, b); a:=[op(a), c];
if c=0 then b:=[op(b), 0]; else b:=[op(b), op(convert(c, base, 10))]; fi; od;
print(op(a)); end: P(10^3);
PROG
(Python)
from itertools import count, islice
def agen(): # generator of terms
s = "1"
yield 1
for n in count(2):
an = s.count(str(n%10))
s += str(an)
yield an
print(list(islice(agen(), 82))) # Michael S. Branicky, Aug 02 2024
(Python)
from collections import Counter
def A375078_gen(): # generator of terms
c, n = Counter({1:1}), 1
yield 1
while True:
n = (n+1)%10
yield c[n]
c += Counter(map(int, str(c[n])))
A375078_list = list(islice(A375078_gen(), 30)) # Chai Wah Wu, Aug 03 2024
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Paolo P. Lava, Jul 29 2024
STATUS
approved