OFFSET
1,1
COMMENTS
Equivalently, indices k for which A016813(k) is a multiple of 49. - Bruno Berselli, May 10 2018
Numbers k such that k == 12 (mod 49). - Joerg Arndt, May 11 2018
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..5000
Jahgwon Ju, Universal sums of generalized pentagonal numbers, arXiv:1805.03434 [math.NT], 2018, page 5 (see Case 4-1).
Index entries for linear recurrences with constant coefficients, signature (1,1,-1).
FORMULA
G.f.: x*(12 + 25*x - 37*x^2)/(1-x)^3.
a(n) = a(n-1) + a(n-2) - a(n-3).
a(n) = 49*n - 37. - Bruno Berselli, May 11 2018
MATHEMATICA
Table[49 n - 37, {n, 1, 50}] (* Bruno Berselli, May 11 2018 *)
PROG
(Magma) [49*n-37: n in [1..50]];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, May 10 2018
STATUS
approved