This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A271584 Irregular triangle read by rows: alternate (k-1)*k, k^2, for k = 0 to n. 1
 0, 0, 0, 0, 0, 1, 0, 0, 2, 0, 1, 4, 0, 0, 2, 6, 0, 1, 4, 9, 0, 0, 2, 6, 12, 0, 1, 4, 9, 16, 0, 0, 2, 6, 12, 20, 0, 1, 4, 9, 16, 25, 0, 0, 2, 6, 12, 20, 30, 0, 1, 4, 9, 16, 25, 36, 0, 0, 2, 6, 12, 20, 30, 42, 0, 1, 4, 9, 16, 25, 36, 49 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,9 COMMENTS This is the irregular triangle e(n) mentioned in A269837. Last number: 0, 0, 0, 1, 2, 4, 6, 9, 12, 16, 20, 25, ... = A002620 with a third initial 0. Row sums: 0, 0, 0, 1, 2, 5, 8, 14, 20, 30, 40, ... = A006918 with three initial 0. Columns: the sum of the first two terms is A000384(n). LINKS EXAMPLE Irregular triangle: 0, 0, 0, 0, 0, 1, 0, 0, 2, 0, 1, 4, 0, 0, 2, 6, 0, 1, 4, 9, 0, 0, 2, 6, 12, 0, 1, 4, 9, 16, 0, 0, 2, 6, 12, 20, 0, 1, 4, 9, 16, 25, etc. MATHEMATICA Flatten[Transpose /@ Table[{k (k - 1), k^2}, {n, 0, 7}, {k, 0, n}]] (* Michael De Vlieger, Apr 10 2016 *) CROSSREFS Cf. A000290, A000384, A002262, A006918, A161680, A269837. Sequence in context: A257920 A258210 A258228 * A072737 A061290 A099096 Adjacent sequences:  A271581 A271582 A271583 * A271585 A271586 A271587 KEYWORD nonn,tabf AUTHOR Paul Curtz, Apr 10 2016 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.

Last modified December 10 15:09 EST 2019. Contains 329896 sequences. (Running on oeis4.)