A093124 a(n) = Sum_{i=n-k..n} sigma(i) which is not less than a(n-1) and obtained with the least k.

1, 3, 4, 7, 13, 18, 20, 23, 28, 31, 43, 58, 72, 78, 90, 93, 97, 112, 132, 150, 151, 169, 193, 194, 225, 225, 233, 253, 259, 271, 272, 293, 301, 355, 403, 408, 446, 506, 562, 580, 590, 623, 667, 703, 727, 751, 799, 832, 851, 884, 900, 908, 920, 944, 972, 1008, 1010, 1028, 1040

Offset

1,2

Comments

Is this sequence well defined?

Links

Table of n, a(n) for n=1..59.

Example

a(1) to a(4) are sigma(n) as these increase: 1 3 4 7. sigma(5)=6 and as this decreases, we examine sigma(5)+sigma(4)=7+6=13.

Prog

(PARI) lista(nn) = my(v=vector(nn)); v[1]=sigma(1); for (i=2, nn, k=0; while (sum(j=i-k, i, sigma(j))<v[i-1], k++); v[i]=sum(j=i-k, i, sigma(j))); v; \\ edited by Michel Marcus, Dec 28 2022

Crossrefs

Cf. A000203, A093125.

Sequence in context: A076784 A279815 A088764 * A055664 A089374 A029552

Adjacent sequences: A093121 A093122 A093123 * A093125 A093126 A093127

Keyword

nonn

Author

Jon Perry, Mar 22 2004

Extensions

Name edited by and more terms from Michel Marcus, Dec 28 2022

Status

approved