A254955 - OEIS

%I #24 Sep 08 2022 08:46:11

%S 3,13,37,71,113,181,263,359,463,601,743,911,1091,1291,1511,1747,2017,

%T 2297,2617,2903,3271,3617,4003,4409,4831,5297,5743,6247,6761,7297,

%U 7853,8443,9029,9631,10271,10973,11717,12413,13109,13879,14717,15461,16301,17191,18059

%N Prime numbers indexed by oblong numbers.

%F a(n) = prime(n + n^2) = A000040(A002378(n)).

%e a(1) = prime(1 + 1^2) = prime(2) = 3.

%e a(2) = prime(2 + 2^2) = prime(6) = 13.

%t Table[Prime[n + n^2], {n, 100}] (* Puszkarz *)

%t Prime[2Accumulate[Range[40]]] (* _Alonso del Arte_, Feb 11 2015 *)

%o (PARI) vector(80, n, prime(n+n^2)) \\ _Michel Marcus_, Feb 12 2015

%o (Magma) [NthPrime(n+n^2): n in [1..50]]; // _Vincenzo Librandi_, Feb 24 2015

%Y Cf. A000040, A002378 (n*(n+1)), A011756 (prime(n(n+1)/2)), A011757 (prime(n^2)).

%K nonn

%O 1,1

%A _Waldemar Puszkarz_, Feb 11 2015