A258016 Unlucky numbers removed at the stage three of Lucky sieve.

19, 39, 61, 81, 103, 123, 145, 165, 187, 207, 229, 249, 271, 291, 313, 333, 355, 375, 397, 417, 439, 459, 481, 501, 523, 543, 565, 585, 607, 627, 649, 669, 691, 711, 733, 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

Offset: 1

Author

Antti Karttunen, Jul 27 2015

Keywords

• nonn
• easy

Comments

Numbers congruent to 19 or 39 modulo 42. - Jianing Song, Apr 27 2022

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000
• Index entries for linear recurrences with constant coefficients, signature (1,1,-1)

Crossrefs

Row 3 of A255543. Every seventh term of A047241.

Cf. also A258011.

Formula

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

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

From Jianing Song, Apr 27 2022: (Start)

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

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

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

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