A255418 Row 8 of Ludic array A255127.

23, 145, 271, 403, 523, 655, 781, 911, 1037, 1157, 1289, 1417, 1543, 1673, 1801, 1927, 2057, 2183, 2305, 2437, 2563, 2693, 2819, 2951, 3071, 3197, 3331, 3457, 3587, 3713, 3841, 3967, 4093, 4223, 4349, 4477, 4603, 4735, 4855, 4987, 5113, 5237, 5369, 5489, 5621, 5747, 5875, 6001

Offset: 1

Author

Antti Karttunen, Feb 22 2015

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10001

Crossrefs

Row 8 of A255127. See A255417 for row 7 and A255419 for row 9.

Programs

PARI

my(L=vector(3913910, x, 3*x+1+x%2), m(n, k)=2^(n\/k*k)\(2^k-1)); for(i=3, 7, L=vecextract(L, 2^#L-m(#L, L[1])-1)); L255418=vecextract(L, m(#L, L[1]));
A255418(n, P=92160)=n--\P*11741730 + L255418[n%P+1] \\ M. F. Hasler, Nov 17 2024

Python

# S can be decreased if only terms up to a smaller limit are needed.
def A255418(n, S=11741730, P=92160):
    try: n-=1; return A255418.L[n]
    except IndexError: return A255418.L[n%P] + n//P*S
    except AttributeError: L = [x+5-x%2 for x in range(0, S, 3)]
    while (k:=L[0]) < 23: L = [x for i, x in enumerate(L) if i%k]
    A255418.L = L[::k]; return A255418(n+1) # M. F. Hasler, Nov 17 2024

Scheme

(define (A255418 n) (A255127bi 8 n)) ;; Code for A255127bi given in A255127.

Formula

a(n) = a(n-P) + S = a((n-1)%P + 1) + S*floor((n-1)/P) with period P = 92160 = A377469(8) and shift S = 11741730 = A376237(9). - M. F. Hasler, Nov 17 2024