A340113 - OEIS

%I #15 Jan 15 2023 18:33:46

%S 2,3,5,7,127,131,137,139,149,151,157,173,179,211,233,251,271,277,281,

%T 311,331,353,421,431,433,443,463,521,523,541,547,571,577,613,631,641,

%U 653,733,743,751,757,761,769,827,853,857,877,887,953,971,983

%N Acronym primes: primes which are the sums of primes and also equal the concatenation of the initial digits of these primes.

%H Eric Angelini, <a href="https://mailman.xmission.com/cgi-bin/mailman/private/math-fun/2020-December/036335.html">Sum of peculiar primes</a>, math-fun mailing list, Dec 24, 2020.

%e The single-digit primes trivially satisfy the constraint.

%e 127 is prime and the concatenation of the initial digits of the primes (19, 29, 79) and also equal to their sum.

%e 131 is prime and the concatenation of the initial digits of the primes (109, 3, 17) and also equal to their sum.

%o (PARI) select( {is_A340113(n)=is_A340112(n) && isprime(n)}, [1..999]) \\ or: {A340113_upto(N)=select(is_A340112,primes([1,N]))}

%Y These are the primes in the sequence of prime-acronyms A340112.

%K nonn,base

%O 1,1

%A _Eric Angelini_ and _M. F. Hasler_, Dec 28 2020