A151981 Numbers n such that n^2 - n is divisible by 48.

0, 1, 16, 33, 48, 49, 64, 81, 96, 97, 112, 129, 144, 145, 160, 177, 192, 193, 208, 225, 240, 241, 256, 273, 288, 289, 304, 321, 336, 337, 352, 369, 384, 385, 400, 417, 432, 433, 448, 465, 480, 481, 496, 513, 528, 529, 544, 561, 576, 577, 592, 609, 624, 625, 640, 657, 672

Offset

1,3

Comments

Numbers congruent to {0, 1, 16, 33} mod 48. - Charles R Greathouse IV, Apr 10 2012

Links

Table of n, a(n) for n=1..57.

Index entries for linear recurrences with constant coefficients, signature (1,0,0,1,-1).

Formula

From Colin Barker, Apr 10 2012: (Start)

G.f.: x^2*(1+15*x+17*x^2+15*x^3)/((1-x)^2*(1+x)*(1+x^2)).

a(n) = a(n-1) + a(n-4) - a(n-5) for n>5. (End)

a(n) = 12*n-(35+3*i^(2*n))/2+(2+2*i)*i^(-n)+(2-2*i)*i^n where i=sqrt(-1). - Wesley Ivan Hurt, Jun 07 2016

Maple

A151981:=n->12*n-(35+3*I^(2*n))/2+(2+2*I)*I^(-n)+(2-2*I)*I^n: seq(A151981(n), n=1..100); # Wesley Ivan Hurt, Jun 07 2016

Mathematica

Table[12n-(35+3*I^(2*n))/2+(2+2*I)*I^(-n)+(2-2*I)*I^n, {n, 80}] (* Wesley Ivan Hurt, Jun 07 2016 *)

Prog

(PARI) a(n)=n\4*48+[-15, 0, 1, 16][n%4+1] \\ Charles R Greathouse IV, Apr 10 2012
(Magma) [n : n in [0..800] | n mod 48 in [0, 1, 16, 33]]; // Wesley Ivan Hurt, Jun 07 2016

Crossrefs

Sequence in context: A119349 A070591 A181452 * A110472 A110502 A095784

Adjacent sequences: A151978 A151979 A151980 * A151982 A151983 A151984

Keyword

nonn,easy

Author

N. J. A. Sloane, Aug 23 2009

Status

approved