cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A371877 Divide primes into groups with Fibonacci(n) elements and add together.

Original entry on oeis.org

2, 3, 12, 41, 139, 442, 1349, 4093, 12108, 35153, 101295, 289048, 819477, 2309689, 6472406, 18054351, 50153807, 138847614, 383282511, 1054875523, 2895955030, 7931352725, 21678032713, 59142462326, 161068803147, 437935857313, 1188967702870, 3223626641605, 8729120815845, 23609318259832
Offset: 1

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Author

Harish Chalwadi, May 24 2024

Keywords

Examples

			The primes and the groups of them summed begin
  primes 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, ...
         \/ \/ \--/  \--------/  \----------------/
  F(n) =  1, 1,  2,      3,               5,      group length
  a(n) =  2, 3, 12,     41,             139,      group sum
a(1) = 2 because the first f(1)=1 prime is 2.
a(2) = 3 because the next f(2)=1 prime is 3.
a(3) = 12 because the next f(2)=2 primes are 5 and 7 which add up to 12.
a(4) = 41 because the next f(3)=3 primes are 11, 13 and 17, and they add up to 41.
		

Crossrefs

Programs

  • Mathematica
    With[{m = 30}, Plus @@@ TakeList[Prime[Range[Fibonacci[m + 2] - 1]], Fibonacci[Range[m]]]] (* Amiram Eldar, May 25 2024 *)
  • PARI
    a371877(nterms) = {my (n1=0, n2=1, p=1); for (n=1, nterms, n1=n2; n2=n1+fibonacci(n); my(s=0); for(k=n1, n2-1, s+=p=nextprime(p+1)); print1 (s, ", "))};
    a371877(30) \\ Hugo Pfoertner, May 25 2024

Extensions

a(11)-a(23) from Michel Marcus, May 25 2024
a(24)-a(30) from Hugo Pfoertner, May 25 2024