A079789 a(n) = number of nonnegative integers m <= n having at least one digit in common with n.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 5, 6, 7, 8, 9, 10, 11, 12, 5, 14, 5, 8, 9, 10, 11, 12, 13, 14, 7, 16, 17, 7, 11, 12, 13, 14, 15, 16, 9, 18, 19, 20, 9, 14, 15, 16, 17, 18, 11, 20, 21, 22, 23, 11, 17, 18, 19, 20, 13, 22, 23, 24, 25, 26, 13, 20, 21, 22, 15, 24, 25, 26, 27, 28, 29

Offset

0,11

Links

Robert Israel, Table of n, a(n) for n = 0..10000

Example

a(10) = 3 and the numbers m are: 0,1,10. a(14) = 7 with m = 1,4,10,11,12,13,14.

Maple

S:= Array(0..10000, n -> convert(convert(n, base, 10), set)):
f:= proc(n) nops(select(t -> S[t] intersect S[n] <> {}, [$0..n])) end proc:
map(f, [$0..100]); # Robert Israel, Dec 03 2024

Prog

(Python)
from collections import Counter
from itertools import count, islice
def agen(): # generator of terms
    dig_sets = dict()
    for n in count(0):
        ss = set(str(n))
        key = "".join(sorted(ss))
        if key not in dig_sets:
            dig_sets[key] = [ss, 0]
        dig_sets[key][1] += 1
        c = sum(dig_sets[k][1] for k in dig_sets if dig_sets[k][0]&ss)
        yield c
print(list(islice(agen(), 77))) # Michael S. Branicky, Dec 03 2024

Crossrefs

Sequence in context: A161560 A078796 A201929 * A131209 A116592 A152772

Adjacent sequences: A079786 A079787 A079788 * A079790 A079791 A079792

Keyword

easy,nonn,base,look

Author

Amarnath Murthy, Feb 04 2003

Extensions

Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 19 2003

Status

approved