A067865 Numbers n such that n and 2^n end with the same two digits.

36, 136, 236, 336, 436, 536, 636, 736, 836, 936, 1036, 1136, 1236, 1336, 1436, 1536, 1636, 1736, 1836, 1936, 2036, 2136, 2236, 2336, 2436, 2536, 2636, 2736, 2836, 2936, 3036, 3136, 3236, 3336, 3436, 3536, 3636, 3736, 3836, 3936, 4036, 4136, 4236, 4336

Offset: 1

Author

Benoit Cloitre, Mar 07 2002

Keywords

• easy
• nonn
• base

Comments

2^36=68719476736 hence 36 is in the sequence.

Links

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

Crossrefs

Cf. A064541.

Subsequence of A067844.

Programs

PARI

isok(n) = (2^n - n) % 100 == 0; \\ Michel Marcus, Nov 23 2013

Formula

a(n) = 36+100(n-1).

a(n) = 2*a(n-1)-a(n-2). G.f.: 4*x*(9+16*x)/(1-x)^2. [Colin Barker, Dec 01 2012]