A320863 Powers of 2 with initial digit 7.

70368744177664, 72057594037927936, 73786976294838206464, 75557863725914323419136, 77371252455336267181195264, 79228162514264337593543950336, 713623846352979940529142984724747568191373312, 730750818665451459101842416358141509827966271488

Offset

1,1

Links

Muniru A Asiru, Table of n, a(n) for n = 1..170

Index to divisibility sequences

Maple

select(x->"7"=""||x[1], [2^n$n=0..180])[];

Mathematica

Select[2^Range[160], First[IntegerDigits[#]] == 7 &] (* G. C. Greubel, Oct 27 2018 *)

Prog

(GAP) Filtered(List([0..180], n->2^n), i->ListOfDigits(i)[1]=7);
(PARI) select(x->(digits(x)[1]==7), vector(200, n, 2^n)) \\ Michel Marcus, Oct 27 2018
(Magma) [2^n: n in [1..160] | Intseq(2^n)[#Intseq(2^n)] eq 7]; // G. C. Greubel, Oct 27 2018

Crossrefs

Cf. A000079 (powers of 2), A008952 (leading digit of 2^n), A217400 (numbers starting with 7).

Powers of 2 with initial digit k, (k = 1..7): A067488, A067480, A320859, A320860, A320861, A320862, this sequence.

Sequence in context: A186018 A233843 A234066 * A139575 A317874 A185432

Adjacent sequences: A320860 A320861 A320862 * A320864 A320865 A320866

Keyword

base,nonn

Author

Muniru A Asiru, Oct 26 2018

Status

approved