A091790 Palindromes obtained as the concatenation of three successive terms of A091789.

1221, 221122, 2112222112, 1222211221122221, 22112211222211222211221122, 211222211222211221122221122112222112222112, 12222112211222211221122221122221122112222112222112211222211221122221

Offset

1,1

Comments

a(13) with 1220 digits is the first term > 10^1000. - Michael S. Branicky, Jul 01 2022

Links

Michael S. Branicky, Table of n, a(n) for n = 1..12

Prog

(Python)
from itertools import count, islice
def agen():
    s, t = "1", "2"
    while True:
        u = (s+t)[::-1]
        yield int(s+t+u)
        s, t = t, u
print(list(islice(agen(), 7))) # Michael S. Branicky, Jul 01 2022

Crossrefs

Cf. A091789.

Sequence in context: A233660 A015279 A179140 * A053655 A068262 A328991

Adjacent sequences: A091787 A091788 A091789 * A091791 A091792 A091793

Keyword

base,nonn

Author

Amarnath Murthy, Feb 18 2004

Extensions

More terms from Max Alekseyev, Sep 19 2009

Status

approved