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A320728 Numbers that are sums of consecutive odd squares (or centered octagonal numbers). 5

%I #40 Mar 14 2020 03:22:57

%S 0,1,9,10,25,34,35,49,74,81,83,84,121,130,155,164,165,169,202,225,251,

%T 276,285,286,289,290,361,371,394,420,441,445,454,455,514,515,529,596,

%U 625,645,650,670,679,680,683,729,802,804,841,875,885,934,959,961,968,969,970,1044,1089

%N Numbers that are sums of consecutive odd squares (or centered octagonal numbers).

%H <a href="/index/Su#ssq">Index entries for sequences related to sums of squares</a>

%o (PARI) ok(n)={my(i=sqrtint(n)); i=i-(i%2==0); while(i>0, my(a=i^2, j=i); while(j>0 && a<=n, if(a==n, return(1)); j-=2; a=a+j^2); i-=2); 0}

%o concat([0], select(ok, [1..1200])) \\ _Antonio Roldán_, Mar 12 2020

%Y Cf. A000447, A016754, A034705, A152043, A322610, A322611, A322637, A322638, A322640.

%K nonn

%O 1,3

%A _Ilya Gutkovskiy_, Dec 21 2018

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Last modified April 25 07:07 EDT 2024. Contains 371964 sequences. (Running on oeis4.)