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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).
2
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
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
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
Sequence in context: A272607 A224552 A039473 * A146170 A367708 A217857
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Jul 13 2019
STATUS
approved