A007599 -id:A007599 - cp's OEIS frontend

A059983 First occurrence of n in A007599.

1, 0, 6, 7, 8, 9, 12, 13, 14, 15, 18, 19, 22, 23, 24, 25, 28, 29, 32, 33, 36, 37, 40, 41, 42, 43, 46, 47, 50, 51, 54, 55, 58, 59, 62, 63, 66, 67, 70, 71, 74, 75, 76, 77, 80, 81, 84, 85, 88, 89, 92, 93, 96, 97, 100, 101, 104, 105, 108, 109, 112, 113, 116, 117, 120, 121, 124

Offset: 0

Robert G. Wilson v, Mar 07 2001

nonn

			a(5) does not appear in A007599 until the 9th entry, keeping in mind the offset.

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Cf. A007599.

import Data.List (elemIndex)
import Data.Maybe (mapMaybe)
a059983 n = a059983_list !! n
a059983_list = mapMaybe (`elemIndex` a007599_list) [0..]
-- Reinhard Zumkeller, Jan 05 2012

a[n_Integer] := a[n] = (a[n - 1] + Nest[a, n - 2, Floor[n/2] ] ); a[0] = 1; a[1] = 0; b[n_Integer] := (k = 0; While[ a[k] != n, k++ ]; k); Table[ b[n], {n, 0, 75} ]

A081408 a(n) = (n+1)*a(n-5), with a(0)=a(1)=a(2)=a(3)=a(4)=1.

Original entry on oeis.org

1, 1, 1, 1, 1, 6, 7, 8, 9, 10, 66, 84, 104, 126, 150, 1056, 1428, 1872, 2394, 3000, 22176, 31416, 43056, 57456, 75000, 576576, 848232, 1205568, 1666224, 2250000, 17873856, 27143424, 39783744, 56651616, 78750000, 643458816, 1004306688, 1511782272

Offset: 0

Labos Elemer, Apr 01 2003

nonn

Quintic factorial sequences are generated by single 5-order recursion and appear in unified form.

			A008548, A034323, A034300, A034301, A034325 sequences are combed together as A081408(5n+r) with r=0,1,2,3,4.

Reinhard Zumkeller, Table of n, a(n) for n = 0..1000

Cf. A001147, A002866, A034001, A007599, A034000, A007696, A000407, A034176, A034177, A008548, A034323, A034300, A034301, A034325 [double, triple, quartic, quintic, factorial subsequences], generated together in A081405-A081408.

a:=[1,1,1,1,1];; for n in [6..40] do a[n]:=n*a[n-5]; od; a; # G. C. Greubel, Aug 15 2019

a081407 n = a081408_list !! n
a081407_list = 1 : 1 : 1 : 1 : zipWith (*) [5..] a081407_list
-- Reinhard Zumkeller, Jan 05 2012

[n le 5 select 1 else n*Self(n-5): n in [1..40]]; // G. C. Greubel, Aug 15 2019

a[0]=a[1]=a[2]=a[3]=a[4]=1; a[x_]:= (x+1)*a[x-5]; Table[a[n], {n, 40}]

m=30; v=concat([1,1,1,1,1], vector(m-5)); for(n=6, m, v[n]=n*v[n-5] ); v \\ G. C. Greubel, Aug 15 2019

def a(n):
    if (n<5): return 1
    else: return (n+1)*a(n-5)
[a(n) for n in (0..40)] # G. C. Greubel, Aug 15 2019

cp's OEIS Frontend

A059983 First occurrence of n in A007599.

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