A239659 Sum of first n parts of the spiral described in A239660.

1, 4, 6, 8, 15, 18, 21, 33, 37, 41, 56, 61, 64, 69, 78, 87, 93, 99, 127, 134, 141, 153, 165, 173, 181, 189, 220, 229, 238, 277, 287, 297, 339, 350, 355, 360, 371, 389, 407, 419, 431, 491, 504, 509, 522, 543, 564, 578, 584, 590, 604, 660, 675, 690, 762, 778, 794, 857, 874, 881, 888, 905, 932, 959, 977, 989, 1007, 1098

Offset

1,2

Comments

We can find the spiral on the terraces of the stepped pyramid described in A244050. - Omar E. Pol, Dec 07 2016

Links

Table of n, a(n) for n=1..68.

Example

If written as an irregular triangle in which row lengths is A237271 the sequence begins:
1;
4;
6, 8;
15;
18, 21;
33;
37, 41;
56;
61, 64, 69;
78, 87;
93, 99;
127;
134, 141;
153, 165;
173, 181, 189;
220;
229, 238;
277;
287, 297;
339;
350, 355, 360, 371;
389, 407;
419, 431;
491;
504, 509, 522;
...
Right border gives A024916.

Crossrefs

Partial sums of A237270.

Cf. A000203, A024916, A196020, A237593, A237271, A239660, A244050, A245092, A262626.

Sequence in context: A302636 A000937 A138001 * A154387 A095299 A079250

Adjacent sequences: A239656 A239657 A239658 * A239660 A239661 A239662

Keyword

nonn,tabf

Author

Omar E. Pol, Mar 31 2014

Status

approved