A049614 -id:A049614 - cp's OEIS frontend

A117734 Absolute difference between the n-th primorial and the n-th compositorial number.

0, 1, 5, 2, 26, 6, 186, 18, 1518, 17070, 14970, 205050, 177330, 2873010, 43515570, 696699570, 696219090, 12540622290, 12531433110, 250812956310

Offset: 1

Roger L. Bagula, Apr 14 2006

nonn

Cf. A034386, A117683.

f[n_] := If[PrimeQ[n] == True, 1, n] cf[0] = 1; cf[n_Integer?Positive] := cf[n] = f[n]*cf[n - 1] g[n_] := If[PrimeQ[n] == True, n, 1] p[0] = 1; p[n_Integer?Positive] := p[n] = g[n]*p[n - 1] Table[Abs[ -cf[n] + p[n]], {n, 1, 20}]

a(n) = | A034386(n)-A049614(n)| .

Offset and A-number corrected; comment rewritten; information duplicating A117733 removed - The Assoc Eds of the OEIS, Oct 20 2010

A222255 Primes of the form n!/n# + 1, where n#=A034386(n) (primorial), listed with repetition.

Original entry on oeis.org

2, 2, 2, 2, 5, 5, 193, 2903041, 250822656001, 1807729046323200001, 1472038679443987759104000001, 21817028147643299474152432146548259236610048000000000001

Offset: 1

M. F. Hasler, Mar 27 2013

nonn

For each n >= 0, if n!/n#+1 is prime, then this prime is listed here: This explains the repetitions.

The next term is already 126 digits long.

for(n=0,99,ispseudoprime(a=n!/prod(k=1,primepi(n),prime(k))+1)&print1(a","))

a(n) = A049614(A140294(n))+1, where A049614 = A000142/A034386.

cp's OEIS Frontend

A117734 Absolute difference between the n-th primorial and the n-th compositorial number.

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