A139595 - OEIS

%I #13 Apr 20 2024 10:27:29

%S 0,5,13,26,42,63,87,116,148,185,225,270,318,371,427,488,552,621,693,

%T 770,850,935,1023,1116,1212,1313,1417,1526,1638,1755,1875,2000,2128,

%U 2261,2397,2538,2682,2831,2983,3140,3300,3465,3633,3806

%N A139277(n) followed by A139273(n+1).

%C Sequence found by reading the line from 0, in the direction 0, 5,... and the same line from 0, in the direction 0, 13,..., in the square spiral whose vertices are the triangular numbers A000217.

%H Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a>.

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,-2,1)

%F Array read by rows: row n gives 8*n^2 + 5n, 8*(n+1)^2 - 3(n+1).

%F G.f.: -x*(5+3*x) / ( (1+x)*(x-1)^3 ). - _R. J. Mathar_, Feb 13 2011

%e Array begins:

%e 0, 5

%e 13, 26

%e 42, 63

%e 87, 116

%t LinearRecurrence[{2,0,-2,1},{0,5,13,26},50] (* _Harvey P. Dale_, Jul 31 2021 *)

%Y Cf. A000217, A046092, A139273, A139277, A077221, A139591, A139592, A139593, A139596, A139597, A139598.

%K easy,nonn

%O 0,2

%A _Omar E. Pol_, May 03 2008