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A305992 The sequence whose indicator function is I in conjectured formula A300997(n) = 2*n - Sum_{k=1..n} I(k), as long as the conjecture holds. 1
1, 2, 4, 8, 15, 24, 32, 48, 62, 80, 101, 122, 147, 171, 202, 230, 267, 299, 339, 377, 418, 464, 509, 559, 611, 664, 719, 776, 836, 896, 960, 1024, 1098, 1167, 1240, 1315, 1392, 1471, 1553, 1642, 1724, 1816, 1906, 1999, 2094, 2190, 2290, 2392, 2499, 2599, 2713, 2818, 2937, 3048, 3166, 3288 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A300997(n) is believed to be equal to 2*n - Sum_{k=1..n} I(k), where I is the indicator function of some other sequence -- let it be this sequence. This sequence is finite if the conjecture is false.

LINKS

Table of n, a(n) for n=1..56.

Indicator function

PROG

(C)

#include <stdio.h>

#include <string.h>

#define N 10000

void e(int *t, int *s) {

  int T[N], i = 0; memset(T, 0, sizeof(T));

  while (i < *s) {

    int f = t[i] / 2;

    T[i] += f + (t[i] % 2);

    T[++ i] += f;

  }

  if (T[*s] != 0) { *s += 1; }

  for (i = 0; i < *s; i ++) { t[i] = T[i]; }

}

int f(int n) {

  int t[N], s = 1, i = 0; t[0] = n;

  while (s != n) { i ++; e(t, &s); }

  return 2 * n - i;

}

int main() {

  int n, last = 1, current;

  for (n = 1; n <= N; n ++) {

    current = f(n);

    switch (current - last) {

    case 0: break;

    case 1: printf("%d, ", n); fflush(stdout); break;

    default: fprintf(stderr, "CONJECTURE IS FALSE"); return;

    }

    last = current;

  }

  printf("\n");

}

CROSSREFS

Cf. A300997.

Sequence in context: A279858 A026474 A301629 * A082562 A159243 A325840

Adjacent sequences:  A305989 A305990 A305991 * A305993 A305994 A305995

KEYWORD

nonn

AUTHOR

Luc Rousseau, Jun 16 2018

STATUS

approved

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Last modified August 17 11:06 EDT 2019. Contains 326057 sequences. (Running on oeis4.)