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A308055 a(1)=2; for n > 1, a(n) is the square root of the smallest square with a(n-1) as a prefix in base 10. 3
2, 5, 23, 48, 22, 15, 39, 63, 251, 501, 224, 474, 689, 2625, 5124, 22637, 47579, 68978, 83053, 28819, 53684, 2317, 4814, 6939, 26342, 51325, 71642, 84642, 290933, 1705676, 4129984, 20322363, 45080332, 67141889, 25911752, 16097128, 12687446, 35619442, 59682026 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The sequence contains the following squares: 315844, 289, 81, 9, and is eventually periodic. - Rémy Sigrist, Jul 13 2019

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..100

Rémy Sigrist, PARI program for A308055

FORMULA

From Rémy Sigrist, Jul 13 2019: (Begin)

a(n+1) = A018851(a(n)).

a(n + 4) = a(n) for n >= 83.

(End)

EXAMPLE

a(1) = 2;

25 is the smallest square with 2 as a prefix;

a(2) = sqrt(25) = 5;

529 is the smallest square with 5 as a prefix;

a(3) = sqrt(529) = 23;

2304 is the smallest square with 23 as a prefix;

a(4) = sqrt(2304) = 48; etc.

PROG

(PARI) See Links section.

CROSSREFS

Cf. A000290 (squares), A018851.

Sequence in context: A175444 A233443 A156314 * A173396 A023186 A023188

Adjacent sequences:  A308052 A308053 A308054 * A308056 A308057 A308058

KEYWORD

nonn,base,easy,look

AUTHOR

Sean Lipton, May 09 2019

EXTENSIONS

a(31)-a(39) from Jon E. Schoenfield, May 10 2019

Comments corrected by Rémy Sigrist, Jul 13 2019

STATUS

approved

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Last modified September 22 03:54 EDT 2020. Contains 337289 sequences. (Running on oeis4.)