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A049852
Concatenate "n" and "nextprime(n)".
1
12, 23, 35, 45, 57, 67, 711, 811, 911, 1011, 1113, 1213, 1317, 1417, 1517, 1617, 1719, 1819, 1923, 2023, 2123, 2223, 2329, 2429, 2529, 2629, 2729, 2829, 2931, 3031, 3137, 3237, 3337, 3437, 3537, 3637, 3741, 3841, 3941, 4041, 4143, 4243
OFFSET
1,1
COMMENTS
From Petros Hadjicostas, Nov 20 2019: (Start)
Version 1 of the "next prime" function is A007918: smallest prime >= n. PARI/GP's nextprime() is version 1.
Maple's nextprime() is the version 2 that appears in A151800: smallest prime > n. We use version 2 here. (End)
EXAMPLE
From Petros Hadjicostas, Nov 20 2019: (Start)
a(1) = 12 because nextprime(1) = 2.
a(2) = 23 because nextprime(2) = 3.
a(3) = 35 because nextprime(3) = 5.
a(4) = 45 because nextprime(4) = 5.
...
a(10) = 1011 because nextprime(10) = 11.
a(11) = 1113 because nextprime(11) = 13.
... (End)
MAPLE
a:= n-> parse(cat(n, nextprime(n))):
seq(a(n), n=1..50); # Alois P. Heinz, Nov 20 2019
PROG
(PARI) a(n) = eval(concat(Str(n), Str(nextprime(n+1)))); \\ Michel Marcus, Jan 01 2017
CROSSREFS
Cf. A007918 (version 1 of nextprime), A151800 (version 2 of nextprime).
Sequence in context: A112131 A233032 A088997 * A045532 A255729 A341740
KEYWORD
nonn,base
STATUS
approved