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A212016 Sums of the squares of two or more consecutive integers. 5
1, 2, 5, 6, 10, 13, 14, 15, 19, 25, 28, 29, 30, 31, 35, 41, 44, 50, 54, 55, 56, 60, 61, 69, 77, 85, 86, 90, 91, 92, 96, 105, 110, 113, 121, 126, 135, 139, 140, 141, 145, 146, 149, 154, 170, 174, 181, 182, 190, 194, 195, 199, 203, 204, 205, 209, 218 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Subsequence of A062861.

Contains A212015 as a subsequence.

A174069 is a subsequence. - Altug Alkan, Dec 24 2015

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

N:= 1000: # to get all terms <=N

g:= x -> x*(x+1)*(2*x+1)/6:

S:= select(`<=`, {seq(seq(g(b)-g(a), a= -b-1 .. b-2), b = 1..floor((sqrt(2*N-1)+1)/2))}, N):

sort(convert(S, list)); # Robert Israel, Jan 05 2016

PROG

(PARI) { isA212016(t) = fordiv(6*t, k, if(k==1, next); z=(k^2-1)/3; if(issquare(4*t/k-z), return(k)); if(z>4*t/k, break); ); 0 }

CROSSREFS

Cf. A062861, A174069, A212015.

Sequence in context: A187902 A187231 A162340 * A212015 A255341 A089269

Adjacent sequences:  A212013 A212014 A212015 * A212017 A212018 A212019

KEYWORD

nonn,easy

AUTHOR

Max Alekseyev, Apr 26 2012

STATUS

approved

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Last modified July 23 22:38 EDT 2019. Contains 325278 sequences. (Running on oeis4.)