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A261995 The first of four consecutive positive integers the sum of the squares of which is equal to the sum of the squares of twenty-one consecutive positive integers. 2
42, 123, 315, 1827, 4659, 13650, 34794, 201114, 512610, 1501539, 3827187, 22120875, 56382603, 165155802, 420955938, 2433095298, 6201573882, 18165636843, 46301326155, 267618362067, 682116744579, 1998054897090, 5092724921274, 29435586732234, 75026640329970 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
For the first of the corresponding twenty-one consecutive positive integers, see A261996.
LINKS
FORMULA
G.f.: -3*x*(6*x^8+8*x^6+27*x^5-596*x^4+504*x^3+64*x^2+27*x+14) / ((x-1)*(x^8-110*x^4+1)).
EXAMPLE
42 is in the sequence because 42^2 + ... + 45^2 = 7574 = 8^2 + ... + 28^2.
PROG
(PARI) Vec(-3*x*(6*x^8+8*x^6+27*x^5-596*x^4+504*x^3+64*x^2+27*x+14)/((x-1)*(x^8-110*x^4+1)) + O(x^40))
CROSSREFS
Sequence in context: A113518 A044293 A044674 * A298236 A299362 A304613
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Sep 08 2015
STATUS
approved

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Last modified May 21 04:01 EDT 2024. Contains 372720 sequences. (Running on oeis4.)