A364662 Numbers k such that sigma(k) < sigma(k+1) < sigma(k+2) < sigma(k+3).

1, 61, 73, 133, 145, 193, 253, 397, 457, 481, 493, 553, 565, 613, 625, 661, 673, 733, 757, 793, 817, 853, 913, 973, 997, 1033, 1093, 1213, 1237, 1285, 1321, 1453, 1513, 1537, 1645, 1657, 1681, 1813, 1825, 1873, 1933, 2077, 2113, 2173, 2233, 2245, 2293, 2413, 2497, 2533, 2581, 2593, 2653, 2713

Offset

1,2

Links

Seiichi Manyama, Table of n, a(n) for n = 1..10000

Prog

(PARI) isok(n) = sigma(n)<sigma(n+1) && sigma(n+1)<sigma(n+2) && sigma(n+2)<sigma(n+3);

Crossrefs

Cf. A050944, A053224, A364659.

Sequence in context: A139944 A179012 A227980 * A227520 A033236 A260808

Adjacent sequences: A364659 A364660 A364661 * A364663 A364664 A364665

Keyword

nonn,easy

Author

Seiichi Manyama, Aug 01 2023

Status

approved