A042976 Decimal expansion of 0.121121112...^2.

0, 1, 4, 6, 7, 0, 3, 2, 3, 7, 9, 9, 0, 3, 4, 7, 6, 9, 1, 0, 3, 6, 7, 6, 9, 9, 0, 4, 8, 5, 6, 9, 9, 2, 1, 6, 7, 6, 8, 2, 2, 1, 2, 5, 7, 0, 1, 0, 5, 2, 3, 4, 7, 8, 2, 3, 2, 5, 6, 5, 7, 0, 1, 2, 1, 4, 7, 8, 8, 2, 2, 1, 2, 7, 4, 5, 7, 0, 7, 2, 5, 6, 5, 7, 0, 1, 0, 2, 4, 3, 9, 1, 9, 0, 3, 2, 5, 6, 7

Offset

0,3

Links

Table of n, a(n) for n=0..98.

Charles Vanden Eynden, Problem 10439. An irrational mimic of 1/9, Amer. Math. Monthly, 104 (1997), 873.

Formula

Equals (1/9 + Sum_{k>=1} 1/10^(k*(k+3)/2))^2. - Amiram Eldar, Apr 18 2026

Mathematica

RealDigits[(1/9 + Sum[1/10^(k*(k+3)/2), {k, 1, Infinity}])^2, 10, 120, -1][[1]] (* Amiram Eldar, Apr 18 2026 *)

Crossrefs

Cf. A042974.

Sequence in context: A348958 A348348 A382583 * A090142 A086237 A200410

Adjacent sequences: A042973 A042974 A042975 * A042977 A042978 A042979

Keyword

nonn,cons

Author

N. J. A. Sloane

Status

approved