A019521 Concatenate squares.

1, 14, 149, 14916, 1491625, 149162536, 14916253649, 1491625364964, 149162536496481, 149162536496481100, 149162536496481100121, 149162536496481100121144, 149162536496481100121144169, 149162536496481100121144169196, 149162536496481100121144169196225

Offset

1,2

Comments

a(3)=149 is the only prime up to n=4000. - Daniel Arribas, Jun 04 2016

References

S. Smarandoiu, Convergence of Smarandache continued fractions, Abstract 96T-11-195, Abstracts Amer. Math. Soc., Vol. 17, No. 4 (1996), p. 680.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..225

Y. Guo and M. Le, Smarandache Concatenated Power Decimals and Their Irrationality, Smarandache Notions Journal, Vol. 9, No. 1-2 (1998), pp. 100-102.

F. Smarandache, Collected Papers, Vol. II.

Eric Weisstein's World of Mathematics, Consecutive Number Sequences.

Maple

a:= proc(n) a(n):= `if`(n=1, 1, parse(cat(a(n-1), n^2))) end:
seq(a(n), n=1..20);  # Alois P. Heinz, Jan 13 2021

Prog

(Haskell)
a019521 n = a019521_list !! (n-1)
a019521_list = f "" $ tail a000290_list where
   f xs (q:qs) = (read ys :: Integer) : f ys qs
     where ys = xs ++ show q
-- Reinhard Zumkeller, Mar 01 2014
(Python)
def a(n): return int("".join(str(i*i) for i in range(1, n+1)))
print([a(n) for n in range(1, 16)]) # Michael S. Branicky, Jan 14 2021

Crossrefs

Cf. A000290, A007908, A038397.

Sequence in context: A081184 A032343 A222614 * A009614 A009802 A153598

Adjacent sequences: A019518 A019519 A019520 * A019522 A019523 A019524

Keyword

base,nonn

Author

R. Muller

Status

approved