A345057 Distance to the next larger number k > n for which A011772(k) = A011772(n), or 0 if no such number exists.

0, 4, 0, 10, 5, 0, 14, 12, 3, 0, 44, 6, 13, 14, 0, 46, 17, 18, 38, 4, 0, 11, 230, 6, 25, 13, 90, 0, 29, 10, 62, 40, 33, 34, 70, 0, 37, 57, 39, 20, 41, 28, 86, 4, 0, 23, 1034, 40, 7, 25, 102, 78, 53, 9, 0, 28, 114, 145, 1652, 60, 61, 62, 63, 190, 260, 0, 134, 68, 23, 140, 284, 24, 73, 37, 25, 38, 154, 0

Offset

1,2

Links

Table of n, a(n) for n=1..78.

Formula

a(n) = A345056(n) - n.

Prog

(PARI)
A011772(n) = { if(n==1, return(1)); my(f=factor(if(n%2, n, 2*n)), step=vecmax(vector(#f~, i, f[i, 1]^f[i, 2]))); forstep(m=step, 2*n, step, if(m*(m-1)/2%n==0, return(m-1)); if(m*(m+1)/2%n==0, return(m))); }; \\ From A011772
A345057(n) = { my(x=A011772(n), y=binomial(x+1, 2)); for(i=1+n, y, if(A011772(i)==x, return(i-n))); (0); };

Crossrefs

Cf. A000217 (positions of zeros), A002024, A011772, A066561, A345056, A345058.

Sequence in context: A331451 A164735 A293933 * A158976 A211243 A181626

Adjacent sequences: A345054 A345055 A345056 * A345058 A345059 A345060

Keyword

nonn

Author

Antti Karttunen, Jun 07 2021

Status

approved