A064757 a(n) = n*11^n - 1.

10, 241, 3992, 58563, 805254, 10629365, 136410196, 1714871047, 21221529218, 259374246009, 3138428376720, 37661140520651, 448795257871102, 5316497670165373, 62658722541234764, 735195677817154575, 8592599484487994106, 100078511642860166657

Offset

1,1

Comments

Conjecture: satisfies a linear recurrence having signature (23, -143, 121). - Harvey P. Dale, May 12 2019

This conjecture is true since a(n) - a(n-1) yields the recurrence 1 + 10*n + 11*n*a(n-1) - (n-1)*a(n) = 0 with polynomial coefficients in n. - Georg Fischer, Feb 19 2021

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..900

Paul Leyland, Factors of Cullen and Woodall numbers

Paul Leyland, Generalized Cullen and Woodall numbers

Index entries for linear recurrences with constant coefficients, signature (23,-143,121).

Maple

k:= 11; f:= gfun:-rectoproc({1 + (k-1)*n + k*n*a(n-1) - (n-1)*a(n) = 0, a(1) = k-1}, a(n), remember): map(f, [$1..20]); # Georg Fischer, Feb 19 2021

Mathematica

Table[n*11^n-1, {n, 20}] (* Harvey P. Dale, May 12 2019 *)

Prog

(Magma) [n*11^n - 1: n in [1..20]]; // Vincenzo Librandi, Sep 16 2011

Crossrefs

For a(n)=n*k^n-1 cf. -A000012(k=0), A001477(k=1), A003261 (k=2), A060352 (k=3), A060416 (k=4), A064751 (k=5), A064752 (k=6), A064753 (k=7), A064754 (k=8), A064755 (k=9), A064756 (k=10), this sequence (k=11), A064758 (k=12).

Sequence in context: A171204 A156443 A211088 * A087435 A331611 A122836

Adjacent sequences: A064754 A064755 A064756 * A064758 A064759 A064760

Keyword

nonn,easy

Author

N. J. A. Sloane, Oct 19 2001

Status

approved