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Unlucky numbers removed at the stage three of Lucky sieve.
3

%I #11 May 05 2022 12:32:52

%S 19,39,61,81,103,123,145,165,187,207,229,249,271,291,313,333,355,375,

%T 397,417,439,459,481,501,523,543,565,585,607,627,649,669,691,711,733,

%U 753,775,795,817,837,859,879,901,921,943,963,985,1005,1027,1047,1069,1089,1111,1131,1153,1173,1195,1215,1237,1257,1279,1299,1321,1341,1363,1383,1405

%N Unlucky numbers removed at the stage three of Lucky sieve.

%C Numbers congruent to 19 or 39 modulo 42. - _Jianing Song_, Apr 27 2022

%H Antti Karttunen, <a href="/A258016/b258016.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1)

%F a(n) = A047241(7*n).

%F a(n) = A260436(A255413(1+n)).

%F From _Jianing Song_, Apr 27 2022: (Start)

%F a(n) = a(n-2) + 42.

%F a(n) = a(n-1) + a(n-2) - a(n-3).

%F G.f.: (19*x+20*x^2+3*x^3)/(1-x-x^2+x^3).

%F E.g.f.: 3 + (21*x-3)*cosh(x) + (21*x-2)*sinh(x). (End)

%o (Scheme, two alternatives)

%o (define (A258016 n) (A047241 (* n 7)))

%o (define (A258016 n) (A255543bi 3 n)) ;; Code for A255543bi given in A255543.

%Y Row 3 of A255543. Every seventh term of A047241.

%Y Cf. also A258011.

%K nonn,easy

%O 1,1

%A _Antti Karttunen_, Jul 27 2015