A101943 Write n in base 5 as n = b_0 + b_1*5 + b_2*5^2 + b_3*5^3 + ...; then a(n) = Product_{i >= 0} prime(i+1)^b_i.

1, 2, 4, 8, 16, 3, 6, 12, 24, 48, 9, 18, 36, 72, 144, 27, 54, 108, 216, 432, 81, 162, 324, 648, 1296, 5, 10, 20, 40, 80, 15, 30, 60, 120, 240, 45, 90, 180, 360, 720, 135, 270, 540, 1080, 2160, 405, 810, 1620, 3240, 6480, 25, 50, 100, 200, 400, 75, 150, 300, 600

Offset: 0

Author

Orges Leka (oleka(AT)students.uni-mainz.de), Dec 21 2004

Keywords

• base
• nonn
• easy

Examples

			a(29) = a(4 + 0*5 + 1*5^2) = 2^4 * 3^0 * 5^1 = 80.
		

Crossrefs

Cf. A019565 (base 2), A101278 (base 3), A101942 (base 4), A054842 (base 10).

Programs

Maple

a:= n-> (l-> mul(ithprime(i)^l[i], i=1..nops(l)))(convert(n, base, 5)):
seq(a(n), n=0..60);  # Alois P. Heinz, Aug 31 2024

Mathematica

f[n_Integer, base_Integer] /; base >= 2 := Product[ Prime[i]^IntegerDigits[n, base][[Length[IntegerDigits[n, base]] + 1 - i]], {i, Length[IntegerDigits[n, base]]}] Table[f[i, 5], {i, 0, 45}]

PARI

f(n, b) = { my(d = digits(n,b), L = #d); prod(i=1, L, prime(i)^d[L+1-i]) }
apply(n -> f(n, 5), [0..45]) \\ Satish Bysany, Mar 07 2017