5,1

a(n) counts the solutions to the inequality x_1^(1/2)+x_2^(1/2)+x_3^((1/2)<=n for any three distinct integers 1<=x_1<x_2<x_3. - R. J. Mathar, Jul 03 2009

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

B. K. Agarwala and F. C. Auluck, Statistical mechanics and partitions into non-integral powers of integers, Proc. Camb. Phil. Soc., 47 (1951), 207-216.

B. K. Agarwala, F. C. Auluck, Statistical mechanics and partitions into non-integral powers of integers, Proc. Camb. Phil. Soc., 47 (1951), 207-216.

A000397 := proc(n) local a, x1, x2, x3 ; a := 0 ; for x1 from 1 to n^2 do for x2 from x1+1 to floor( (n-x1^(1/2))^2 ) do x3 := (n-x1^(1/2)-x2^(1/2))^2 ; if floor(x3) >= x2+1 then a := a+floor(x3-x2) ; fi; od: od: a ; end: for n from 5 do printf("%d, \n", A000397(n)) ; od: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 29 2009]

Sequence in context: A161844 A090382 A102359 this_sequence A130410 A027217 A121333

Adjacent sequences: A000394 A000395 A000396 this_sequence A000398 A000399 A000400

nonn

N. J. A. Sloane (njas(AT)research.att.com).

More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 29 2009