A377456 Starts of runs of 3 consecutive integers that are all terms of A377385.

39998374960, 326660221888, 520935101440, 723006782783, 923072388208, 977932351240, 1134397887874, 1351753892944, 1864828904536, 2171452161023

Offset

1,1

Links

Table of n, a(n) for n=1..10.

Example

39998374960 is a term since 39998374960, 39998374961 and 39998374962 are all in A377385: 39998374960/A034968(39998374960) = 999959374, and 999959374/A034968(999959374) = 32256754 are integers, 39998374961/A034968(39998374961) = 975570121, and 975570121/A034968(975570121) = 33640349 are integers, and 39998374962/A034968(39998374962) = 1025599358, and 1025599358/A034968(1025599358) = 30164687 are integers.

Prog

(PARI) fdigsum(n) = {my(k = n, m = 2, r, s = 0); while([k, r] = divrem(k, m); k != 0 || r != 0, s += r; m++); s; }
is1(k) = {my(f = fdigsum(k)); !(k % f) && !((k/f) % fdigsum(k/f)); }
lista(kmax) = {my(q1 = is1(1), q2 = is1(2), q3); for(k = 3, kmax, q3 = is1(k); if(q1 && q2 && q3, print1(k-2, ", ")); q1 = q2; q2 = q3); }

Crossrefs

Cf. A034968.

Subsequence of A118363, A328205, A377385 and A377455.

Analogous sequences: A376794 (binary), A377273 (Zeckendorf).

Sequence in context: A216018 A256842 A225886 * A199428 A287261 A172631

Adjacent sequences: A377453 A377454 A377455 * A377457 A377460 A377462

Keyword

nonn,base,more

Author

Amiram Eldar, Oct 29 2024

Status

approved