A139264 a(n) = 70*n - 63.

7, 77, 147, 217, 287, 357, 427, 497, 567, 637, 707, 777, 847, 917, 987, 1057, 1127, 1197, 1267, 1337, 1407, 1477, 1547, 1617, 1687, 1757, 1827, 1897, 1967, 2037, 2107, 2177, 2247, 2317, 2387, 2457, 2527, 2597, 2667, 2737, 2807, 2877, 2947, 3017, 3087, 3157, 3227

Offset: 1

Author

Odimar Fabeny, Jun 06 2008

Keywords

• easy
• nonn

Comments

Multiples of 7 with unit digit equal to 7.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..2000
• Index entries for linear recurrences with constant coefficients, signature (2,-1).

Crossrefs

Subsequence of A034709, together with A017281, A017293, A139222, A139245, A017329, A139249, A139279 and A139280.

Programs

Magma

[70*n-63: n in [1..50]]; // Vincenzo Librandi, Jun 19 2011

Mathematica

70*Range[50]-63 (* Harvey P. Dale, May 06 2019 *)

PARI

a(n)=70*n-63 \\ Charles R Greathouse IV, Aug 25 2014

Formula

a(n) = a(n-1) + 70.

From Elmo R. Oliveira, Apr 04 2025: (Start)

G.f.: 7*x*(1+9*x)/(1-x)^2.

E.g.f.: 7*(exp(x)*(10*x - 9) + 9).

a(n) = 7*A017281(n-1).

a(n) = 2*a(n-1) - a(n-2) for n > 2. (End)

Extensions

More terms from Reinhard Zumkeller, Jun 22 2008