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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.

%I A381224 #19 Feb 22 2025 14:06:48
%S A381224 0,2,3,5,71,11,31,71,92,32,93,13,74,14,34,75,35,96,16,77,17,37,98,38,
%T A381224 99,710,110,310,710,911,312,713,113,713,914,915,115,716,316,717,317,
%U A381224 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
%N 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.
%C A381224 Take list of primes and move the right-most digit of each term to the start of the next term.
%C A381224 Inspired by _Eric Angelini_ and _Carole Dubois_'s A339467.
%H A381224 N. J. A. Sloane, <a href="/A381224/b381224.txt">Table of n, a(n) for n = 1..10000</a>
%e A381224 Starting from
%e A381224    2, 3, 5, 7, 11, 13, 17, 19, ...
%e A381224 we get
%e A381224    0, 2, 3, 5, 71, 11, 31, 71, ...
%p A381224 a381224 := proc(n) local i,p;
%p A381224 if n=1 then i:=0; else i:=(ithprime(n-1) mod 10); fi;
%p A381224 p:=ithprime(n);
%p A381224 i * 10^ilog10(p) + floor(p/10);
%p A381224 end;
%o A381224 (Python)
%o A381224 from sympy import prime
%o A381224 def a(n): return 0 if n == 1 else int(str(prime(n-1)%10)+ str(prime(n))[:-1])
%o A381224 print([a(n) for n in range(1, 73)]) # _Michael S. Branicky_, Feb 22 2025
%Y A381224 Cf. A000040, A032759, A290148, A339467.
%K A381224 nonn,base,look
%O A381224 1,2
%A A381224 _N. J. A. Sloane_, Feb 22 2025