A085931 - OEIS

%I #10 Dec 15 2017 17:44:30

%S 2,4,12,17,23,39,48,58,69,95,109,124,140,157,195,215,236,258,281,305,

%T 357,384,412,441,471,502,534,602,637,673,710,748,787,827,868,954,998,

%U 1043,1089,1136,1184,1233,1283,1334,1440,1494,1549,1605,1662,1720,1779

%N Leading diagonal of A085930.

%H Gheorghe Coserea, <a href="/A085931/b085931.txt">Table of n, a(n) for n = 1..10000</a>

%H T. Forbes, <a href="http://anthony.d.forbes.googlepages.com/adf.htm">Prime k-tuplets</a>

%o (PARI)

%o a(n) = my(x = (sqrtint(1+8*n)-1)\2); (x+n)*(x+n+1)/2 - n;

%o vector(51, n, a(n))  \\ _Gheorghe Coserea_, Mar 25 2016

%Y Cf. A085930.

%K easy,nonn

%O 1,1

%A _Jason Earls_ and _Amarnath Murthy_, Jul 14 2003

%E Offset corrected by _Gheorghe Coserea_, Mar 25 2016