A391734 Right edge of triangle A240673: a(n) = A002110(n-1) * A079276(n).

1, 4, 6, 120, 210, 6930, 450450, 9189180, 193993800, 2677114440, 116454478140, 5415133233510, 51945166943670, 1521251317636050, 562558737261811290, 1229779565176982820, 130356633908760178920, 19227603501542126390700, 4456958491657464897364260, 23574964653240801167637270, 33476449807601937658044923400, 814593611984980483012426469400

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..349

Index entries for sequences related to primorial numbers.

Formula

Apparently, for n >= 3, a(n) = A245458(n) - 2.

Prog

(PARI)
A002110(n) = prod(i=1, n, prime(i));
A079276(n) = lift(prod(i=1, n-1, Mod(1/prime(i), prime(n))));
A391734(n) = (A002110(n-1) * A079276(n));
(PARI)
A240673_tr(n, k) = { my(val = prod(j=1, n, prime(j))/prime(k)); val * lift(1/Mod(val, prime(k))); }; \\ The function "T" in A240673.
A391734(n) = A240673_tr(n, n);

Crossrefs

Right edge of triangle A240673.

Cf. A002110, A079276, A245458.

Sequence in context: A367878 A012934 A013165 * A337466 A052672 A381971

Adjacent sequences: A391731 A391732 A391733 * A391735 A391736 A391737

Keyword

nonn

Author

Antti Karttunen, Dec 31 2025

Status

approved