A171762 a(n) = Sum_{k=n^2+1..(n+1)^2-1} tau(k).

4, 12, 22, 34, 44, 58, 72, 88, 100, 120, 126, 148, 164, 182, 196, 220, 228, 254, 264, 284, 304, 328, 338, 358, 382, 400, 420, 444, 442, 478, 494, 518, 544, 564, 562, 602, 622, 648, 652, 690, 684, 730, 740, 768, 790, 812, 828, 858, 870, 898, 920, 946, 958, 990

Offset: 1

Author

Giovanni Teofilatto, Dec 18 2009

Keywords

• nonn
• easy

Crossrefs

Cf. A000005, A048691, A168011.

Programs

Maple

A168011 := proc(n) add( numtheory[tau](k),k=1..n^2+2*n) ; end proc: A048691 := proc(n) numtheory[tau](n^2) ; end proc: A171762 := proc(n) A168011(n)-A168011(n-1)-A048691(n) ; end proc: seq(A171762(n),n=1..80) ; # R. J. Mathar, Jan 25 2010

Mathematica

Array[n \[Function] Sum[DivisorSigma[0, k], {k, n^2 + 1, (n + 1)^2 - 1}], 200] (* J. Mulder (jasper.mulder(AT)planet.nl), Jan 28 2010 *)

Formula

a(n) = A168011(n) - A168011(n-1) - A048691(n). - R. J. Mathar, Jan 25 2010

Extensions

Definition corrected by Giovanni Teofilatto, Dec 19 2009

More terms from R. J. Mathar and J. Mulder (jasper.mulder(AT)planet.nl), Jan 25 2010