A347181 Lexicographically earliest sequence of distinct positive integers such that the first digit of a(n) is visible in a(n) + a(n+1).

1, 9, 10, 2, 18, 3, 20, 4, 30, 5, 40, 6, 50, 7, 60, 8, 70, 17, 14, 27, 15, 16, 25, 37, 26, 36, 47, 57, 28, 24, 38, 35, 48, 46, 58, 67, 19, 12, 29, 13, 68, 78, 39, 34, 49, 45, 59, 56, 69, 77, 80, 88, 90, 79, 91, 98, 11, 89, 92, 87, 21, 31, 22, 99, 93, 66, 94, 55, 95, 44, 96, 23, 97, 32, 41, 33, 100, 42

Offset

1,2

Links

Table of n, a(n) for n=1..78.

Example

a(1) + a(2) =  1 +  9 = 10;
a(2) + a(3) =  9 + 10 = 19;
a(3) + a(4) = 10 +  2 = 12;
a(4) + a(5) =  2 + 18 = 20;
a(5) + a(6) = 18 +  3 = 21; etc.

Prog

(Python)
def aupton(terms):
    alst, aset = [1], {1}
    while len(alst) < terms:
        an, target = 2, str(alst[-1])[0]
        while an in aset or target not in str(alst[-1]+an): an += 1
        alst.append(an); aset.add(an)
    return alst
print(aupton(200)) # Michael S. Branicky, Aug 21 2021

Crossrefs

Cf. A347180.

Sequence in context: A126839 A341818 A034058 * A333774 A205151 A167691

Adjacent sequences: A347178 A347179 A347180 * A347182 A347183 A347184

Keyword

base,nonn

Author

Eric Angelini and Carole Dubois, Aug 21 2021

Status

approved