0,3

Starting with offset 1 = binomial transform of A068193: (1, 6, 18, 42, 90,...) and double binomial transform of (1, 5, 7, 5, 7, 5,...). [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Jan 13 2009]

Ballot, Christian and Luca, Florian, Prime factors of a^f(n)-1 with an irreducible polynomial f(x). New York J. Math. 12 (2006), 39-45 (electronic).

Ballot, Christian and Luca, Florian, Common prime factors of a^n-b and c^n-d. Unif. Distrib. Theory 2 (2007), no. 2, 19-34 (electronic).

Index entries for sequences related to linear recurrences with constant coefficients

a(n)=Sum(i!*i^2*Stirling2(n,i)*(-1)^(n-i), i=1,..,n)

a_n = 6a_{n-1} - 11a_{n-2} + 6a_{n-3}, g.f.: x(1+x)/(1-x)(2-x)(3-x)). - Christian Ballot via R. K. Guy, Jan 13 2009

a:=n->sum((3^(n-j-1)-2^(n-2-j))*12, j=0..n): seq(a(n), n=-1..24); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 11 2007

with (combinat):a:=n->stirling2(n, 3)+stirling2(n+1, 3): seq(a(n), n=1..26); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Oct 07 2007

Table[Sum[i!i^2 StirlingS2[n, i](-1)^(n - i), {i, 1, n}], {n, 0, 30}]

A068293 [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Jan 13 2009]

Sequence in context: A055580 A097786 A006458 this_sequence A032197 A114289 A147597

Adjacent sequences: A091341 A091342 A091343 this_sequence A091345 A091346 A091347

easy,nonn

Mario Catalani (mario.catalani(AT)unito.it), Jan 01 2004

Edited by N. J. A. Sloane (njas(AT)research.att.com), Jan 13 2009 at the suggestion of R. K. Guy. The concise definition was provided by Vladeta Jovovic (vladeta(AT)eunet.rs), Jan 01 2004.