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A025294 Numbers that are the sum of 2 nonzero squares in 3 or more ways. 2
325, 425, 650, 725, 845, 850, 925, 1025, 1105, 1250, 1300, 1325, 1445, 1450, 1525, 1625, 1690, 1700, 1825, 1850, 1885, 2050, 2125, 2210, 2225, 2405, 2425, 2465, 2525, 2600, 2650, 2665, 2725, 2825, 2873, 2890, 2900, 2925, 3050, 3125, 3145, 3250, 3380 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A025426(a(n)) > 2. - Reinhard Zumkeller, Feb 26 2015

LINKS

Robert Israel and Reinhard Zumkeller, Table of n, a(n) for n = 1..10000, first 2508 terms by Robert Israel

Index entries for sequences related to sums of squares

MAPLE

  N:= 100000: # generate all entries <=N

SSQ:= {}: SSQ2:= {}: SSQ3:= {}:

for a from 1 to floor(sqrt(N)) do

  for b from a to floor(sqrt(N-a^2)) do

    n:= a^2 + b^2;

    if member(n, SSQ2) then SSQ3:= SSQ3 union {n}

    elif member(n, SSQ) then SSQ2:= SSQ2 union {n}

    else SSQ:= SSQ union {n}

    end if

end do end do:

SSQ3;  # Robert Israel, Jan 20 2013

PROG

(Haskell)

a025294 n = a025294_list !! (n-1)

a025294_list = filter ((> 2) . a025426) [1..]

-- Reinhard Zumkeller, Feb 26 2015

CROSSREFS

Complement of A025285 relative to A007692. - Washington Bomfim, Oct 24 2010

Cf. A025426.

Sequence in context: A159844 A000443 A097101 * A025313 A025286 A025304

Adjacent sequences:  A025291 A025292 A025293 * A025295 A025296 A025297

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified August 17 03:51 EDT 2017. Contains 290631 sequences.