A004957 a(n) = ceiling(n*phi^2), where phi is the golden ratio, A001622.

0, 3, 6, 8, 11, 14, 16, 19, 21, 24, 27, 29, 32, 35, 37, 40, 42, 45, 48, 50, 53, 55, 58, 61, 63, 66, 69, 71, 74, 76, 79, 82, 84, 87, 90, 92, 95, 97, 100, 103, 105, 108, 110, 113, 116, 118, 121, 124, 126, 129, 131, 134

Offset

0,2

Links

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Formula

A060142(a(n)) = 4 * A060142(n). - Reinhard Zumkeller, Nov 26 2012

Prog

(Haskell)
import Data.List (findIndices)
a004957 n = a004957_list !! n
a004957_list = findIndices even a060142_list
-- Reinhard Zumkeller, Nov 26 2012
(Python)
from math import isqrt
def A004957(n): return (n+isqrt(5*n**2)>>1)+n+bool(n) # Chai Wah Wu, Feb 20 2026

Crossrefs

Essentially same as A026352.

Cf. A001622.

Sequence in context: A310136 A310137 A157017 * A026352 A198084 A047399

Adjacent sequences: A004954 A004955 A004956 * A004958 A004959 A004960

Keyword

nonn

Author

N. J. A. Sloane

Status

approved