OFFSET
1,4
EXAMPLE
. n | a(n) | runs in A001358 having a common initial digit
. ----+------+-------------------------------------------------------
. 1 | 1 | [4]
. 2 | 1 | [6]
. 3 | 1 | [9]
. 4 | 3 | [10, 14, 15]
. 5 | 4 | [21, 22, 25, 26]
. 6 | 5 | [33, 34, 35, 38, 39]
. 7 | 2 | [46, 49]
. 8 | 4 | [51, 55, 57, 58]
. 9 | 3 | [62, 65, 69]
. 10 | 2 | [74, 77]
. 11 | 4 | [82, 85, 86, 87]
. 12 | 4 | [91, 93, 94, 95]
. 13 | 28 | [106,111,115,118,119,121,122,123,129,133,134,141,
. | | 142,143,145,146,155,158,159,161,166,169,177,178,
. | | 183,185,187,194,201]
. 14 | 32 | [201,202,203,205,206,209,213,214,215,217,218,219,
. | | 221,226,235,237,247,249,253,254,259,262,265,267,
. | | 274,278,287,289,291,295,298,299]
. 15 | 32 | [301,302,303,305,309,314,319,321,323,326,327,329,
. | | 334,335,339,341,346,355,358,361,362,365,371,377,
. | | 381,382,386,391,393,394,395,398]
. 16 | 27 | [403,407,411,413,415,417,422,427,437,445,446,447,
. | | 451,453,454,458,466,469,471,473,478,481,482,485,
. | | 489,493,497].
PROG
(Haskell)
import Data.List (group)
a239639 n = a239639_list !! (n-1)
a239639_list = map length $ group a239634_list
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Mar 23 2014
STATUS
approved