A347112 a(n) = concat(prime(n+1),n) mod prime(n).

1, 1, 3, 2, 3, 7, 10, 10, 0, 7, 22, 5, 8, 27, 4, 33, 40, 8, 17, 7, 37, 27, 42, 23, 37, 24, 15, 14, 102, 74, 50, 108, 96, 61, 86, 32, 9, 112, 138, 121, 62, 137, 52, 58, 48, 52, 192, 2, 22, 221, 185, 13, 89, 152, 141, 130, 257, 116, 182, 260, 212, 290, 156, 264

Offset: 1

Author

Simon Strandgaard, Aug 18 2021

Keywords

• nonn
• base

Examples

			a(1) = concat( 3,1) mod  2 = 1,
a(2) = concat( 5,2) mod  3 = 1,
a(3) = concat( 7,3) mod  5 = 3,
a(4) = concat(11,4) mod  7 = 2,
a(5) = concat(13,5) mod 11 = 3.
		

Links

• Simon Strandgaard, Plot of 10000 terms

Crossrefs

Cf. A000040, A075110.

Programs

Mathematica

Array[Mod[#3*10^(1 + Floor[Log10[#1]]) + #1, #2] & @@ {#, Prime[#], Prime[# + 1]} &, 64] (* Michael De Vlieger, Aug 18 2021 *)

PARI

a(n) = eval(Str(prime(n+1),n)) % prime(n);

Python

from sympy import prime
def a(n): return int(str(prime(n+1)) + str(n))%prime(n)
print([a(n) for n in range(1, 65)]) # Michael S. Branicky, Aug 18 2021

Ruby

require 'prime'
values = []
primes = Prime.first(50)
primes.each_index do |n|
  next if n < 1
  values << (primes[n].to_s + n.to_s).to_i % primes[n-1]
end
p values