login

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 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A086609
Number of primes between consecutive partition numbers.
1
0, 1, 1, 1, 1, 1, 1, 2, 2, 3, 3, 5, 5, 6, 8, 10, 12, 14, 17, 21, 24, 30, 36, 44, 49, 63, 71, 87, 100, 120, 143, 164, 200, 226, 272, 318, 368, 432, 499, 593, 681, 792, 912, 1069, 1228, 1437, 1641, 1900, 2177, 2530, 2896, 3348, 3832, 4379, 5039, 5775, 6582, 7516
OFFSET
0,8
LINKS
FORMULA
a(n) = A000720(A000041(n+1)) - A000720(A000041(n)).
MATHEMATICA
PrimePi[#[[2]]]-PrimePi[#[[1]]]&/@Partition[PartitionsP[Range[0, 100]], 2, 1] (* Harvey P. Dale, Sep 13 2021 *)
PROG
(PARI) a(n)={primepi(numbpart(n+1)) - primepi(numbpart(n))} \\ Andrew Howroyd, Jan 05 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Sep 11 2003
EXTENSIONS
Terms a(42) and beyond from Andrew Howroyd, Jan 05 2020
STATUS
approved