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A239659 Sum of first n parts of the spiral described in A239660. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

We can find the spiral on the terraces of the step 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

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Last modified September 17 12:57 EDT 2019. Contains 327131 sequences. (Running on oeis4.)