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A309123 a(1) = 50 and for any n > 0, a(n+1)^2 is the smallest square that begins with a(n). 1
50, 71, 267, 517, 2274, 1508, 3884, 1971, 444, 667, 817, 286, 535, 732, 856, 2926, 541, 736, 858, 293, 542, 233, 483, 695, 834, 2888, 16995, 41225, 20304, 4506, 6713, 2591, 5091, 22564, 47502, 21795, 46686, 21607, 46484, 215602, 46433, 68142, 261041, 510922 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

This sequence is similar to A308055.

The initial value (50) seems to be the first one for which the iteration of A018796 diverges; there are neither duplicates nor squares among the first 79000 terms.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..1000

Rémy Sigrist, PARI program for A309123

FORMULA

a(1) = 50 and then a(n+1) = A018796(a(n)) for n > 0.

EXAMPLE

The first terms, alongside the square of a(n+1), are:

  n   a(n)  a(n+1)^2

  --  ----  --------

   1    50      5041

   2    71     71289

   3   267    267289

   4   517   5171076

   5  2274   2274064

   6  1508  15085456

   7  3884   3884841

   8  1971    197136

   9   444    444889

  10   667    667489

  11   817     81796

  12   286    286225

  13   535    535824

  14   732    732736

  15   856   8561476

  16  2926    292681

PROG

(PARI) See Links section.

CROSSREFS

Cf. A018796, A308055.

Sequence in context: A272607 A224552 A039473 * A146170 A217857 A071366

Adjacent sequences:  A309120 A309121 A309122 * A309124 A309125 A309126

KEYWORD

nonn,base

AUTHOR

Rémy Sigrist, Jul 13 2019

STATUS

approved

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Last modified May 31 02:51 EDT 2020. Contains 334747 sequences. (Running on oeis4.)