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

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A262610 The values of sigma function (A000203) and the positive integers interleaved. 0
 1, 1, 3, 2, 4, 3, 7, 4, 6, 5, 12, 6, 8, 7, 15, 8, 13, 9, 18, 10, 12, 11, 28, 12, 14, 13, 24, 14, 24, 15, 31, 16, 18, 17, 39, 18, 20, 19, 42, 20, 32, 21, 36, 22, 24, 23, 60, 24, 31, 25, 42, 26, 40, 27, 56, 28, 30, 29, 72, 30, 32, 31, 63, 32, 48, 33, 54, 34, 48, 35, 91, 36, 38, 37, 60, 38, 56, 39, 90, 40, 42, 41, 96, 42 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS a(n) is also the total area of the n-th symmetric set of regions in the two-dimensional diagram of the perspective view of the infinite stepped pyramid described in A245092 but according with the diagram as shown here in the Links section and assuming that the first square cell at the top of the structure has area = 1. Note that both the top view and the perspective view of the pyramid contain a hidden pattern which emerges from the front view of the pyramid. For more information see A237593, A262626. LINKS Omar E. Pol, Illustration of initial terms (n = 1..32) MAPLE f:= n -> (numtheory:-sigma(n), n): seq(f(n), n=1..100); # Robert Israel, Oct 22 2015 MATHEMATICA t = Range@ 42; Riffle[DivisorSigma[1, t], t] (* Michael De Vlieger, Oct 19 2015 *) PROG (PARI) vector(50, n, if (n % 2, sigma((n+1)/2), n/2)) \\ Michel Marcus, Oct 21 2015 CROSSREFS Cf. A000203, A245092, A236104, A237591, A237593, A237270, A237271, A262626. Sequence in context: A147598 A023869 A024596 * A175508 A065375 A070961 Adjacent sequences:  A262607 A262608 A262609 * A262611 A262612 A262613 KEYWORD nonn,easy AUTHOR Omar E. Pol, Sep 26 2015 EXTENSIONS a(12) corrected by Georg Fischer, Nov 02 2021 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 1 07:59 EST 2021. Contains 349426 sequences. (Running on oeis4.)