login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A334113 Positive numbers not of the form 4*x^4 + y*(y+1)/2 + z*(z+1)/2, where x,y,z are nonnegative integers. 3
23, 44, 54, 63, 117, 138, 149, 162, 180, 188, 243, 251, 261, 270, 287, 294, 398, 401, 458, 512, 611, 657, 684, 693, 734, 797, 842, 863, 914, 932, 936, 945, 987, 1029, 1047, 1098, 1323, 1401, 1449, 1472, 1484, 1494, 1574, 1608, 1637, 1769, 1792, 1799, 1823, 1839, 1902, 1995 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Conjecture: The sequence only has 602 terms as listed in the b-file.

Our computation indicates that after the 602-th term 31737789 there are no other terms below 10^8.

It is known that each n = 0,1,2,... can be written as the sum of an even square and two triangular numbers.

LINKS

Zhi-Wei Sun, Table of n, a(n) for n = 1..602

Zhi-Wei Sun, Mixed sums of squares and triangular numbers, Acta Arith. 127(2007), 103-113.

MATHEMATICA

TQ[n_]:=TQ[n]=IntegerQ[Sqrt[8n+1]];

tab={}; Do[Do[If[TQ[n-4x^4-y(y+1)/2], Goto[aa]], {x, 0, (n/4)^(1/4)}, {y, 0, (Sqrt[4(n-4x^4)+1]-1)/2}]; tab=Append[tab, n]; Label[aa], {n, 0, 2000}]; Print[tab]

CROSSREFS

Cf. A000217, A000583, A115160, A306227, A334086.

Sequence in context: A168439 A332399 A198949 * A214891 A003859 A058545

Adjacent sequences:  A334110 A334111 A334112 * A334114 A334115 A334116

KEYWORD

nonn

AUTHOR

Zhi-Wei Sun, Apr 14 2020

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 26 03:20 EST 2020. Contains 338632 sequences. (Running on oeis4.)