A350521 a(n) = 18*n + 4.

4, 22, 40, 58, 76, 94, 112, 130, 148, 166, 184, 202, 220, 238, 256, 274, 292, 310, 328, 346, 364, 382, 400, 418, 436, 454, 472, 490, 508, 526, 544, 562, 580, 598, 616, 634, 652, 670, 688, 706, 724, 742, 760, 778, 796, 814, 832, 850, 868, 886, 904, 922, 940, 958

Offset: 0

Author

Omar E. Pol, Jan 03 2022

Keywords

• nonn
• easy

Comments

Second column of A006370 (the Collatz or 3x+1 map) when it is interpreted as a rectangular array with six columns read by rows.

Links

• Index entries for linear recurrences with constant coefficients, signature (2,-1).

Crossrefs

Bisection of A017209.

Cf. A006370, A008600, A016921, A017185, A242215, A298035.

Programs

GAP

List([0..53], n-> 18*n+4)

Magma

[18*n+4: n in [0..53]];

Maple

seq(18*n+4, n=0..53);

Mathematica

Table[18n+4, {n, 0, 53}]

Maxima

makelist(18*n+4, n, 0, 53);

PARI

a(n)=18*n+4

Python

[18*n+4 for n in range(53)]

Formula

a(n) = A242215(n) - 1.

a(n) = A298035(n+1) + 1.

From Elmo R. Oliveira, Apr 08 2024: (Start)

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

E.g.f.: 2*exp(x)*(2 + 9*x).

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

a(n) = 2*A017185(n) = A006370(A016921(n)). (End)