A381224 a(n) is the integer resulting from the concatenation of the unit digit of prime(n-1) to the digits of prime(n) without its own unit digit.

0, 2, 3, 5, 71, 11, 31, 71, 92, 32, 93, 13, 74, 14, 34, 75, 35, 96, 16, 77, 17, 37, 98, 38, 99, 710, 110, 310, 710, 911, 312, 713, 113, 713, 914, 915, 115, 716, 316, 717, 317, 918, 119, 119, 319, 719, 921, 122, 322, 722, 923, 323, 924, 125, 125, 726, 326, 927, 127, 728, 128, 329, 330, 731, 131, 331, 733, 133, 734, 734, 935, 335

Offset: 1

Author

N. J. A. Sloane, Feb 22 2025

Keywords

• nonn
• base
• look

Comments

Take list of primes and move the right-most digit of each term to the start of the next term.

Inspired by Eric Angelini and Carole Dubois's A339467.

Examples

			Starting from
   2, 3, 5, 7, 11, 13, 17, 19, ...
we get
   0, 2, 3, 5, 71, 11, 31, 71, ...
		

Links

• N. J. A. Sloane, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A032759, A290148, A339467.

Programs

Maple

a381224 := proc(n) local i,p;
if n=1 then i:=0; else i:=(ithprime(n-1) mod 10); fi;
p:=ithprime(n);
i * 10^ilog10(p) + floor(p/10);
end;

Python

from sympy import prime
def a(n): return 0 if n == 1 else int(str(prime(n-1)%10)+ str(prime(n))[:-1])
print([a(n) for n in range(1, 73)]) # Michael S. Branicky, Feb 22 2025