A008557 Repeatedly convert from decimal to octal.

8, 10, 12, 14, 16, 20, 24, 30, 36, 44, 54, 66, 102, 146, 222, 336, 520, 1010, 1762, 3342, 6416, 14420, 34124, 102514, 310162, 1135622, 4252006, 20160546, 114720042, 665476452, 4752456544, 43321135540, 502611010664, 7240574662150, 151272370273006

Offset: 1

Author

sbv(AT)VNET.IBM.COM (Scott Vetter), msvetter(AT)eng.xyplex.com (Mark Vetter)

Keywords

• nonn
• base
• nice
• easy

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..75

Crossrefs

Cf. A007094, A008558.

Programs

Haskell

a008557 n = a008557_list !! (n-1)
a008557_list = iterate a007094 8  -- Reinhard Zumkeller, Aug 29 2013

Mathematica

NestList[ FromDigits[ IntegerDigits[ #, 8 ]] &, 8, 35 ]

Python

def aupton(terms):
    alst = [8]
    for n in range(2, terms+1): alst.append(int(oct(alst[-1])[2:]))
    return alst
print(aupton(35)) # Michael S. Branicky, Aug 10 2021

Formula

a(n+1) = A007094(a(n)), a(1) = 8. - Reinhard Zumkeller, Aug 29 2013