A067490 Powers of 4 with initial digit 1.

1, 16, 1024, 16384, 1048576, 16777216, 1073741824, 17179869184, 1099511627776, 17592186044416, 1125899906842624, 18014398509481984, 1152921504606846976, 18446744073709551616, 1180591620717411303424, 18889465931478580854784, 1208925819614629174706176

Offset

1,2

Links

Muniru A Asiru, Table of n, a(n) for n = 1..400

Index to divisibility sequences

Formula

a(n+1)/a(n) is in {16, 64, 1024}, so 16^n <= a(n+1) < 1024^n. Asymptotically, the exponent should be 100; I can prove that 99^n << a(n) << 101^n. [Charles R Greathouse IV, Jan 19 2012]

Maple

select(x-> "1"=""||x[1], [4^n$n=0..60])[];  # Alois P. Heinz, Oct 22 2018

Prog

(GAP) Filtered(List([0..40], n->4^n), i->ListOfDigits(i)[1]=1); # Muniru A Asiru, Oct 22 2018

Crossrefs

Cf. A067480, A067481, A067482, A067483, A067484, A067485, A067486, A067487, A067488, A067489.

Sequence in context: A159683 A197104 A358051 * A130036 A013735 A180376

Adjacent sequences: A067487 A067488 A067489 * A067491 A067492 A067493

Keyword

base,easy,nonn

Author

Amarnath Murthy, Feb 09 2002

Extensions

a(16) inserted by Muniru A Asiru, Oct 22 2018

Status

approved