A167657 Product of n-th block of identical consecutive values of A000720.

0, 1, 4, 9, 256, 25, 1296, 49, 4096, 531441, 100, 1771561, 20736, 169, 38416, 11390625, 16777216, 289, 34012224, 130321, 400, 85766121, 234256, 148035889, 110075314176, 390625, 676, 531441, 784, 707281, 478296900000000000000, 923521

Offset

1,3

Links

Jason Kimberley, Table of n, a(n) for n = 1..10000

Formula

a(n) = n^(A000040(n+1)-A000040(n)). - Jason Kimberley, May 27 2018

Maple

A000720 := proc(n) numtheory[pi](n) ; end proc: A167657 := proc(nmax) local ol, a ; ol := 0 ; a := 0 ; for n from 1 to nmax do if A000720(n) = ol then a := a*ol ; else printf("%d, ", a) ; a := A000720(n) ; end if; ol := A000720(n) ; end do ; return ; end proc: A167657(160) ; # R. J. Mathar, Jan 30 2010

Mathematica

Most@ Map[Times @@ # &, Split@ Array[PrimePi, 132]] (* Michael De Vlieger, May 27 2018 *)

Prog

(Magma) A40:=NthPrime;
A167657:=func<n|(n-1)^(A40(n)-A40(n-1))>;
[A167657(n):n in[1..32]]; // Jason Kimberley, May 27 2018

Crossrefs

Cf. A000720.

Sequence in context: A030074 A335723 A299122 * A175700 A035126 A178454

Adjacent sequences: A167654 A167655 A167656 * A167658 A167659 A167660

Keyword

nonn,look

Author

Giovanni Teofilatto, Nov 08 2009

Extensions

a(1) = 0 and a(5) = 256 corrected by Giovanni Teofilatto, Nov 12 2009

a(17) inserted and a(20) corrected by R. J. Mathar, Jan 30 2010

Name edited by Jason Kimberley, Jul 01 2018

Status

approved