A349805 a(n) = A261138(n)/11.

1, 111, 11211, 1122211, 112232211, 11223332211, 1122334332211, 112233444332211, 11223344544332211, 112233444636544332211, 1122334446373736544332211, 11223344463737473736544332211, 112233444637374666473736544332211, 1122334446373746649466473736544332211, 11223344463737466492319466473736544332211

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Maple

a:= n-> (s-> parse(cat(s, seq(s[-i], i=1..length(s))))/11)(cat("", $1..n)):
seq(a(n), n=1..14);  # Alois P. Heinz, Dec 01 2021

Prog

(Python)
def A349805(n): return int((lambda x: x+x[::-1])(''.join(str(d) for d in range(1, n+1))))//11 # Chai Wah Wu, Dec 01 2021

Crossrefs

Cf. A261138.

A109242 has the same initial terms.

Sequence in context: A111864 A098034 A109242 * A165155 A078270 A298677

Adjacent sequences: A349802 A349803 A349804 * A349806 A349807 A349808

Keyword

nonn,base

Author

N. J. A. Sloane, Dec 01 2021

Extensions

More than the usual number of terms are shown in order to distinguish this from several similar sequences.

Status

approved