A320860 Powers of 2 with initial digit 4.

4, 4096, 4194304, 4294967296, 4398046511104, 4503599627370496, 4611686018427387904, 4722366482869645213696, 4835703278458516698824704, 4951760157141521099596496896, 40564819207303340847894502572032, 41538374868278621028243970633760768

Offset: 1

Author

Muniru A Asiru, Oct 22 2018

Keywords

• base
• nonn

Comments

Differs from A067482 first at n = 11.

Links

• Muniru A Asiru, Table of n, a(n) for n = 1..320
• Index to divisibility sequences

Crossrefs

Cf. A000079 (Powers of 2), A008952 (leading digit of 2^n), A217397 (numbers starting with 4).

Powers of 2 with initial digit k, (k = 1..4): A067488, A067480, A320859, this sequence.

Programs

GAP

Filtered(List([0..150],n->2^n),i->ListOfDigits(i)[1]=4);

Magma

[2^n: n in [1..160] | Intseq(2^n)[#Intseq(2^n)] eq 4]; // G. C. Greubel, Oct 27 2018

Maple

select(x->"4"=""||x[1],[2^n$n=0..150])[];

Mathematica

Select[2^Range[160], First[IntegerDigits[#]] == 4 &] (* G. C. Greubel, Oct 27 2018 *)

PARI

select(x->(digits(x)[1]==4), vector(200, n, 2^n)) \\ Michel Marcus, Oct 26 2018