A247431 - OEIS

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A247431

The largest integer m such that A001950(m) < A003231(n).

1, 2, 3, 5, 6, 8, 9, 10, 12, 13, 14, 16, 17, 19, 20, 21, 23, 24, 25, 27, 28, 30, 31, 32, 34, 35, 37, 38, 39, 41, 42, 43, 45, 46, 48, 49, 50, 52, 53, 55, 56, 57, 59, 60, 61, 63, 64, 66, 67, 68, 70, 71, 72, 74, 75, 77, 78, 79, 81, 82, 84, 85, 86, 88, 89, 90, 92

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

This is the function named K in [Carlitz].

LINKS

Table of n, a(n) for n=1..67.

L. Carlitz, R. Scoville, and T. Vaughan, Some arithmetic functions related to Fibonacci numbers, Fib. Quart., 11 (1973), 337-386.

PROG

(PARI) a31(n) = (5*n+sqrtint(5*n^2))\2; \\ A003231

a50(n) = (sqrtint(n^2*5)+n*3)\2; \\ A001950

a(n) = my(m=1, N=a31(n)); while(a50(m) < N, m++); m-1; \\ Michel Marcus, Nov 14 2023